Hot-swap SATA drive cages for a DIY NAS tower

A failed NAS drive should be a front-door job, not an evening of removing side panels and tracing cables. A hot-swap cage gives an older tower a neat row of drive handles—and keeps the data and power connections parked behind them.

Choose ICY DOCK FatCage MB155SP-B for five HDD trays in three external bays, iStarUSA BPN-DE350SS for five trayless slots, or FatCage MB153SP-B when you have only two external bays. Start by opening your tower: these cages need real, contiguous 5.25-inch optical-drive bays, not spare internal HDD mounts.

Specifications and mounting details come from the makers’ pages, manuals and drawings, checked October 25, 2026.

Quick picks: trays, trayless or two bays

Five drives with trays: ICY DOCK FatCage MB155SP-B. You get five front-access 3.5-inch HDD positions, a removable 92 mm fan and a high/low/off speed jumper. The tray carries the drive out of the tower while the backplane wiring stays put. It is the pick for a tower with three adjacent external bays and room behind them for the connectors. MB155SP-B specifications.

Five drives without carriers: iStarUSA BPN-DE350SS. Slide a 3.5-inch HDD into the slot and close the handle; there is no separate tray to screw onto each drive. Its keyed handles and high/low fan switch suit a build where straightforward drive access matters. The linked model is the RED front-panel variant, BPN-DE350SS-RED. iStarUSA specifications and variants.

Three drives in two bays: ICY DOCK FatCage MB153SP-B. This smaller stack uses three trays and an 80 mm replaceable fan. Choose it when your optical-bay opening is shorter, or combine it with a five-drive cage for eight front-access HDDs. MB153SP-B specifications.

Already choosing a whole new enclosure? Compare our compact DIY NAS cases first. A purpose-built drive layout can be a cleaner route than finding a tower with enough optical bays.

Compare the cages

Cage and drive access	Bay conversion, connections and cooling
ICY DOCK MB155SP-B — five trays	3 external 5.25-inch bays → 5 × 3.5-inch HDDs; 5 × 7-pin SATA data inputs; 3 × 15-pin SATA power inputs; 92 × 92 × 25 mm fan, high/low/off; 200.4 mm body depth
iStarUSA BPN-DE350SS-RED — five trayless slots	3 external 5.25-inch bays → 5 × 3.5-inch HDDs; 5 × 7-pin SATA data inputs; 2 × 15-pin SATA power inputs; 80 × 80 × 20 mm fan, high/low; 197.9 mm depth
ICY DOCK MB153SP-B — three trays	2 external 5.25-inch bays → 3 × 3.5-inch HDDs; 3 × 7-pin SATA data inputs; 2 × 15-pin SATA power inputs; 80 × 80 × 25 mm replaceable fan; 200.4 mm body depth

All three exact models take SATA power, not four-pin Molex. They provide individual drive connections; they do not contain a RAID engine or turn one motherboard SATA port into five. The ICY DOCK specifications also require a SAS host for SAS drives. A SAS-capable backplane cannot make a SATA-only controller speak SAS.

Use these picks for 3.5-inch HDDs. For a 2.5-inch SSD array, match the drives to the exact tray’s mounting pattern.

Does your tower actually have the bays?

Pop off the front cover before ordering. Here is the useful fit check:

1. Count contiguous external bays. MB155SP-B and DE350SS need a clear three-bay stack; MB153SP-B needs two. An internal drive bracket or a slim optical slot is a different mounting system.
2. Inspect the side rails and ledges. Compare them with the cage’s full-height side walls and screw positions. A shelf that supports each optical drive can obstruct a multi-bay cage. Choose a compatible tower rather than forcing the cage past metalwork.
3. Measure depth with the motherboard installed. Allow the cage’s stated depth plus connector bodies, cable bends and space for the rear fan to breathe. A radiator, GPU or motherboard connector can occupy the same space.
4. Check the front opening and door. The bezel and handles need to clear the case fascia. Leave room to open a handle and withdraw a whole drive.
5. Keep the ventilation path open. Decorative doors and dense filters can sit directly in front of the cage’s intake. Plan the opening, fan and cable routing together.

The MB155SP-B drawing and MB153SP-B drawing show the mounting holes, body and rear connectors. Use those outlines rather than treating the advertised depth as a complete installed-clearance allowance.

For MB155SP-B, avoid drives using Power Disable (PWDIS): ICY DOCK’s product FAQ says this feature is unsupported and those drives will not spin up. Our NAS hard-drive guide is the place to choose the disks; keep their electrical requirements in the cage plan too.

Plan the cables before filling the trays

Each disk needs its own data channel. For motherboard SATA, that means five or eight SATA ports and matching data leads. For an HBA with SFF-8643 outputs, a suitable forward-breakout lead provides four SATA drive connections. StarTech’s SFF-8643-to-four-SATA datasheet shows that controller-to-drive arrangement. Match the HBA connector and direction; reverse-breakout cables do a different job.

iStarUSA’s manual lists five SATA data cables among the accessories. An SFF-8643 HBA still needs the matching forward-breakout leads rather than those ordinary motherboard leads.

Here are the calculated connector counts at the backplanes for fully populated cages:

Drive plan	External bays / SATA data / SATA power plugs
5 HDDs: one MB155SP-B	3 bays / 5 data / 3 power
5 HDDs: one DE350SS	3 bays / 5 data / 2 power
8 HDDs: MB155SP-B + MB153SP-B	5 bays / 8 data / 5 power
8 HDDs: DE350SS + MB153SP-B	5 bays / 8 data / 4 power

With four-drive forward leads, both five- and eight-drive plans need two leads and enough HBA channels. The five-drive plan leaves three SATA tails unused; the eight-drive plan uses all eight. Secure unused tails away from the fan.

Connect every backplane power input. The MB155SP-B manual calls for all three inputs; the MB153SP-B manual calls for both. iStarUSA labels its two SATA power inputs Power1 and Power2 in the DE350SS manual.

Power-plug count is different from PSU-cable count. Five SATA plugs on a shopping list do not automatically mean five separate PSU harnesses—or that one harness is suitable for every drive’s startup load. Follow the PSU’s cable and load guidance, use cables approved for that exact modular PSU, and include the disks’ spin-up requirements. Our PSU buying guide helps count the available SATA connectors alongside the rest of the build.

Need more host ports? Use the SATA/HBA guide to choose the controller and cables. The cage handles access; the controller supplies the channels.

Keep the fan useful

MB155SP-B gives you a high/low/off jumper; DE350SS has a high/low switch, with high as the documented default. Start with the documented high setting on those models, then watch drive temperatures during sustained use before changing it. Keep MB153SP-B’s 80 mm fan running; its manual shows replaceable two-/three-pin fan connections rather than a speed-selector jumper.

Fan diameter alone cannot rank the finished tower’s noise. Drive vibration, the chosen disks, ventilation and fan speed all contribute. Keep the cage’s exhaust clear, route leads around the blades, and use the quiet-cooling guide for the rest of the enclosure.

Install it, label it, then practise the drive workflow

• Shut down the NAS and disconnect power before mounting the cage or changing its rear wiring.
• Remove the case’s bay covers, secure the cage using the specified mounting screws, and connect the planned data leads and all power inputs.
• Fit HDDs to ICY DOCK’s trays with the specified drive screws. For the trayless iStarUSA, insert the disk and close the handle until it clicks, following its manual.
• Start the machine and check that every expected drive appears. Record each disk’s serial number against its front-slot label while the mapping is easy to establish.
• Verify the fans run and inspect drive health and temperatures under your intended workload. Test the replacement workflow with a spare disk and disposable data before relying on it for a live pool.
• For an actual failure, follow your storage OS’s offline/replace procedure, identify the exact disk, replace it and monitor recovery. TrueNAS documents taking the failed disk offline and replacing it with one of the same or greater capacity; replacement triggers a resilver. TrueNAS disk replacement.

The host controller and operating system must support hot-plugging as well as the cage. When that support is absent, shut down for a drive change. Keep a backup regardless: easier access does not change the recovery plan.

The right cage makes maintenance a front-panel job

Buy MB155SP-B for five removable HDD trays, DE350SS-RED for five trayless slots, or MB153SP-B for a two-bay opening. For eight drives, the five-plus-three combinations give you a clear shopping list: five external bays, eight data channels and the correct four or five SATA power plugs. Get those details right now, and the next drive replacement starts with a labeled handle instead of a cable hunt.