Rack units, mounting depth, and how the shelf is held at the back

The best rack shelves for 2026

A shelf is what holds the equipment that has no rack ears of its own, and three published figures decide it. The first is height in rack units, each 44.45 mm, since a 1U shelf occupies one unit of space and a 2U shelf occupies two — the shelf itself consumes that space, not merely the thing standing on it. The second is depth, and it is the figure that most often goes wrong: a shelf deeper than the cabinet's internal depth will not go in at all, while a shelf far shallower than the equipment leaves it overhanging into the door. The third is the stated load rating, published as a static figure by the maker, and it depends entirely on how the shelf is fixed. That is the real division here. A cantilever shelf bolts to the front posts only and carries less; a four-post shelf is supported front and rear and carries considerably more; a sliding shelf on runners lets equipment be pulled out into the room and gives up some capacity to the mechanism. Read then whether the surface is vented, which counts under anything that runs warm, and whether the edges are lipped so a box cannot walk off the front. The mounting hardware is the last line: cage nuts, bolts and washers are sometimes supplied and sometimes not, and a square-hole rack and a threaded one call for different parts. We compare rack units, mounting depth, cantilever or four-post support, stated load rating, vented or solid surface, sliding or fixed, usable surface dimensions and fixings supplied.

The ones worth keeping in the drawer

1. 

   DIGITUS 19-inch 1U fixed shelf, 250 mm deep, 441 × 250 mm usable, 15 kg

   The cheapest shelf in this hub and one of only two that separate the usable surface from the outer dimension, with its screws, cage nuts and washers all listed in the delivery.

   Rack units

   One — stated in the title and in the second bullet, which says the shelf needs only a single rack unit

   Mounting depth

   250 mm — stated in the title and in the first bullet. The second adds that the shelf fits DIGITUS 19-inch network cabinets from a depth of 450 mm upwards, which is a requirement on the cabinet rather than a dimension of the shelf

   Cantilever or four-post support

   Not published on the listing — the second bullet says the shelf is fixed to the 19-inch profile rails of the network cabinet and does not say whether that means the front rails alone or front and rear. No post count appears anywhere

   Stated load rating

   Up to 15 kg — stated in the fifth bullet, alongside a construction of high-grade steel sheet. It is the lowest load on this shelf apart from the sliding one

   Vented or solid surface

   Vented — the fourth bullet describes the perforation of the shelf as allowing unhindered air circulation in the cabinet and contributing to the cooling of the equipment

   Sliding or fixed

   Fixed — stated in the title as a shelf for fixed installation, and in the second bullet, which describes it bolted to the profile rails

   Usable surface dimensions

   441 × 250 mm in width and depth — stated in the first bullet as the surface inside the shelf, against outer dimensions of 482 × 250 mm. Two of the seven shelves here separate those two figures and this is one of them

   Fixings supplied

   Screws, cage nuts and washers — stated in the fifth bullet as included in the delivery. It is the fullest fixing list on this shelf

   Amazon reference

   DE B002KTE870 · US B07CNGDN63 · GB B07CNGDN63 · FR B07CNGDN63 · IT B07CNGDN63 · ES B07CNGDN63

   EAN

   4016032185772

   • Separates the usable surface from the outer dimension, which five of the seven shelves here never do
   • Screws, cage nuts and washers all listed, so nothing else has to be ordered
   • Fifteen kilograms, the lowest fixed-shelf rating on this shelf

   Best for: A router or a mini-PC standing in a deep cabinet, where the shelf is a platform rather than a load-bearing part.

   ≈ 13 €

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2. 

   STALFLEX 19-inch 1U shelf, rear fixing, variable depth, 25 kg

   A 25 kg perforated shelf sold on a rear fixing and a variable depth, with five bullets of description and not one measurement among them.

   Rack units

   One — stated in the title and in the second bullet, which calls the standard 1U and 19-inch format a guarantee of secure mounting

   Mounting depth

   Not published in the title or in any bullet — the title says variable depth and stops there. The manufacturer reference recorded for this listing reads 150 mm, which is a catalogue string rather than a published specification, and no bullet confirms it

   Cantilever or four-post support

   Neither is named — the title states that the fixing is at the rear, which is not the arrangement either of the two named terms describes. No post count and no front-flange description appears in any bullet

   Stated load rating

   25 kg — stated in the title as the carrying capacity. It sits above three of the fixed shelves on this shelf and well below the four-post one

   Vented or solid surface

   Vented — the first and fourth bullets both describe a perforated shelf, credited with improving air circulation and with preventing equipment overheating

   Sliding or fixed

   Not published on the listing — no bullet says whether the shelf is bolted in place or runs on any kind of slide. The fourth mentions mounting equipment to it with cable ties to stop accidental slipping, which is about the equipment rather than the shelf

   Usable surface dimensions

   Not published on the listing — no width, no depth and no surface figure appears in the title or in any of the five bullets

   Fixings supplied

   Not published on the listing — no screws, no cage nuts and no washers are listed. The second bullet says the standard format guarantees secure mounting and names no hardware

   Amazon reference

   B0D9RT1V64 (same reference on 6 Amazon marketplaces)

   EAN

   5903351265003

   • Twenty-five kilograms, more than two of the three cheaper shelves here carry
   • Perforated, and the page says twice what the perforation is for
   • Not one dimension in five bullets, on a part whose whole job is to fit a space

   Best for: A shallow cabinet where 25 kg has to sit on something and the buyer can confirm the depth with the seller before ordering.

   ≈ 13 €

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3. 

   HB-DIGITAL 19-inch 1U shelf, 270 mm deep, 480 × 265 mm usable, no load figure published

   One of only two shelves here to publish a usable surface — 480 by 265 millimetres — and the only one that calls itself heavy-duty in the title and then never says what it carries.

   Rack units

   One — stated in the title and in the third bullet, which says the 1U shelf maximises the available space and improves air circulation

   Mounting depth

   270 mm — stated in the title

   Cantilever or four-post support

   Not published on the listing — the second bullet claims universal compatibility with 19-inch rack frames and a quick installation without special tools, and no bullet says whether the shelf is carried at the front alone or at both ends

   Stated load rating

   Not published on the listing — no weight figure appears anywhere. The title calls the shelf heavy-duty steel sheet and the first bullet describes a robust construction giving a stable and secure platform, without naming a load. Six of the seven shelves here publish a figure

   Vented or solid surface

   Not published on the listing — no perforation and no vent is named. The third bullet credits the shelf with improving air circulation without saying how, and the fourth describes the usable dimensions rather than the surface

   Sliding or fixed

   Not published on the listing — no bullet says whether the shelf bolts in place or runs on slides. The second describes a quick installation and the fifth a solid steel construction with a black coating

   Usable surface dimensions

   480 mm usable width and 265 mm usable depth — stated in the fourth bullet, which offers the shelf for network hardware and audio-visual equipment alike. Two of the seven shelves here publish a usable figure and this is one of them

   Fixings supplied

   Not published on the listing — no screws, cage nuts or washers are listed. The second bullet says the installation is quick and needs no special tool, which describes the effort rather than the contents

   Amazon reference

   B0DDTGFMGM (same reference on 6 Amazon marketplaces)

   EAN

   4063328058241

   • Publishes a usable width and a usable depth, which five of the seven shelves here never do
   • Two hundred and seventy millimetres of depth, more than the two cheaper shelves offer
   • Called heavy-duty in the title with no load figure anywhere on the page

   Best for: A cabinet where the shelf has to be measured before it is bought, and the weight going on it is modest and already known.

   ≈ 18 €

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4. 

   HMF 19-inch 1U shelf, 300 mm mounting depth, 483 × 300 × 44 mm, 16 kg, cage nuts included

   The shelf that describes its own installation most precisely — fixing points on the front face, at one rack unit — and publishes its own weight alongside the load it will carry.

   Rack units

   One — stated in the title and in the fourth bullet, which puts 1 HE in brackets after the description of the fixing points

   Mounting depth

   300 mm — stated in the title as the installation depth, and in the first bullet as a requirement: the shelf suits 19-inch cabinets offering at least 300 mm of mounting depth

   Cantilever or four-post support

   Neither term is used, and the fourth bullet describes the arrangement plainly: a quick installation on the profile rails thanks to fixing points on the front face. A shelf carried at the front alone is what the cantilever entry in this table describes, and the listing does not use the word

   Stated load rating

   About 16 kg — stated in the fifth bullet alongside the dimensions and the weight. The word about is the maker’s own

   Vented or solid surface

   Not published on the listing — no perforation, no vent and no airflow claim appears in any of the five bullets. The third describes stable steel sheet with a scratch-resistant black powder coating

   Sliding or fixed

   Fixed — stated in the first bullet as a shelf for fixed installation, and confirmed by the fourth, which describes it bolted to the profile rails

   Usable surface dimensions

   Not published on the listing — the fifth bullet gives 483 × 300 × 44 mm as the width, depth and height of the shelf, which are outer dimensions. No separate figure for the flat surface appears

   Fixings supplied

   Cage nuts — named in the fifth bullet as the accessory. No screws and no washers are listed alongside them

   Amazon reference

   B09F1DQCSD (same reference on 5 Amazon marketplaces)

   EAN

   4010537659929

   • Describes the fixing arrangement in plain words, which five of the seven shelves here never do
   • Publishes its own weight, 1.44 kg, as well as the load it carries
   • Nothing says whether the surface is perforated, and this is a cabinet part

   Best for: A 19-inch cabinet of at least 300 mm depth holding a modest, awkward object that needs a stable platform and nothing more.

   ≈ 21 €

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5. 

   KOSCOM CONNECT 19-inch 1U sliding shelf, 483 × 350 × 45 mm, rails adjustable 350–505 mm, 5 kg

   A tray that comes out of the cabinet instead of staying in it, which is the whole argument for it — and a five-kilogram limit, which is the price of the mechanism.

   Rack units

   One — stated in the fourth bullet, which gives the dimensions as 48.3 × 35 × 4.5 cm for a 1U pull-out tray

   Mounting depth

   For cabinets from 450 mm depth — stated in the first and fourth bullets, the latter giving the range as 450 mm up to 600 mm. The third adds that the spacing of the profile rails is adjustable in depth from 35 to 50.5 cm

   Cantilever or four-post support

   Not published on the listing — the third bullet says the tray installs on the profile rails of the rack with an adjustable rail spacing, and no bullet names a post count or says whether the rear is carried

   Stated load rating

   Maximum 5 kg — stated in the second bullet. It is by a wide margin the lowest figure on this shelf, where the fixed trays run from about 15 kg to 110 kg

   Vented or solid surface

   Vented — the second bullet describes high-grade perforated sheet, stable and able to withstand high loads while allowing passive cooling

   Sliding or fixed

   Sliding — stated in the title and in the first bullet as a pull-out tray, offered for components that cannot be rack-mounted and for easier access. It is the only sliding shelf in this hub

   Usable surface dimensions

   Not published on the listing — the fourth bullet gives 48.3 × 35 × 4.5 cm as the dimensions of the tray, which are outer figures. No separate surface measurement appears

   Fixings supplied

   Not published on the listing — no screws, cage nuts or washers are listed. The third bullet says the tray installs easily on the profile rails and names no hardware

   Amazon reference

   B0D96B839H (same reference on 6 Amazon marketplaces)

   EAN

   4043089462211

   • The only shelf in this hub that pulls out, which is the difference between reading a label and moving a cabinet
   • The rail spacing adjusts across 155 mm, from 350 to 505 mm
   • Five kilograms, a third of the 15 kg a fixed tray here carries

   Best for: A cabinet holding something that has to be reached rather than merely stored — a small drive, a console, a labelled patch record.

   ≈ £45 / 35 €

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6. 

   Tecmojo 19-inch 1U four-post shelf, 550 mm deep, adjustable 343 mm upwards, 110 kg

   The only four-post shelf in this hub, and the only one that carries three figures instead of one: 110 kilograms, an adjustable depth, and a hardware list counted item by item.

   Rack units

   One — stated in the title and in the first bullet, which describes a 1U four-post server rack tray for 19-inch racks and cabinets

   Mounting depth

   Adjustable — the title gives a shelf depth of 550 mm and a variable mounting depth from 343 mm to 800 mm, while the first bullet gives the same range as 34.3 cm to 80.8 cm. The lower figure agrees; the upper differs between the two, and neither is withdrawn

   Cantilever or four-post support

   Four-post — stated in the first bullet, which calls it a 1U four-post server rack tray designed for 19-inch racks and cabinets with an adjustable mounting depth. It is the only listing on this shelf to name the arrangement in those words

   Stated load rating

   Up to 110 kg — stated in the title and in the second bullet, which names industrial-grade SPCC cold-rolled steel and gives tower servers, uninterruptible power supplies, NAS units and amplifiers as the equipment it has in mind. It is five times the next highest figure on this shelf

   Vented or solid surface

   Vented — stated in the title as a rack tray with ventilation openings, and in the third bullet, which credits the vented design with constant air circulation and effective heat dissipation

   Sliding or fixed

   Fixed — stated in the title as a shelf for fixed installation, and in the second bullet, which calls it a fixed rack tray

   Usable surface dimensions

   Not published on the listing — the title gives the shelf as 550 mm deep and no width or surface figure appears in any bullet

   Fixings supplied

   Sixteen M6 bolts, eight M6 cage nuts, eight flange nuts, two non-slip stoppers and two hook-and-loop cable ties — listed item by item in the fourth bullet, the only counted hardware list on this shelf

   Amazon reference

   B0GDPBJ17V (same reference on 6 Amazon marketplaces)

   EAN

   5061116020448

   • A hundred and ten kilograms on four posts, five times anything else on this shelf
   • The hardware is listed piece by piece, down to two non-slip stoppers
   • The upper depth figure is 800 mm in the title and 80.8 cm in the first bullet

   Best for: A deep cabinet holding something genuinely heavy — a tower server, an uninterruptible power supply, a stack of drives — where front-only support would not do.

   ≈ 40 €

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7. 

   StarTech two 1U vented cantilever shelves, 25 cm deep, 20 kg each, tested at 1.5 times load

   The only shelf here sold in pairs and the only one whose maker states a test margin above the rating, at a quarter of a metre deep and twenty kilograms a tray.

   Rack units

   One each — stated in the title and in the first bullet, which describes two 1U vented cantilever rack shelves in a set

   Mounting depth

   25 cm — stated in the title. No minimum cabinet depth is named, and no adjustment range appears

   Cantilever or four-post support

   Cantilever — stated in the title and in the first bullet, and detailed in the fourth as SPCC cold-rolled steel with cantilever front mounting. It is one of only two listings on this shelf to name its support arrangement in words

   Stated load rating

   Up to 20 kg per shelf — stated in the title and in the fourth bullet, which adds that the shelves are tested at one and a half times that load. The test is the maker’s statement and no test document is named

   Vented or solid surface

   Vented — stated in the title and in the third bullet, which describes a perforated 1U tray supporting even airflow and reducing hot spots under servers or audio-visual equipment

   Sliding or fixed

   Fixed — the fourth bullet describes cantilever front mounting, and no bullet mentions runners or any pull-out action

   Usable surface dimensions

   Not published on the listing — 25 cm is given as the depth in the title and no width or surface figure appears in any of the five bullets

   Fixings supplied

   Not published on the listing — no screws, cage nuts or washers are listed. The first and second bullets describe fitting out several racks to a consistent layout and name no hardware

   Amazon reference

   B0GZLDHSV1 (same reference on 6 Amazon marketplaces)

   EAN

   0065030937498

   • Two shelves in one pack, which no other listing on this shelf offers
   • Names the cantilever arrangement outright rather than leaving it to be inferred
   • The dearest listing on this shelf, and it is two of the simplest shelves here

   Best for: Two cabinets, or one cabinet being fitted out to a consistent layout, where both trays go in at the same time.

   ≈ $58 / £70 / 76 €

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