The 531611 is a 105 x 60 x 125 mm extruded aluminum "Sink Box" enclosure in a clear anodized finish, built for OEM engineers and electronics designers who need to mount a small printed circuit board or chassis horizontally in a compact, conduction-cooled housing. The 531611 is a short 125 mm length in the 105 x 60 mm profile, finished in clear anodize for a natural aluminum look; the drawing lists 431611 as the black version.

The body is formed from a single, hollow aluminum extrusion, which gives the unit high strength and simplifies assembly. Fins run across the entire top of the extrusion and act as a heat sink, while aluminum end panels close each end and molded black plastic bezels protect the end panels. The series is a British design originally sold under the West Hyde Enclosures Ltd. name.

Inside, numerous slots on both shorter sides accept a P.C. board or chassis; the manufacturer drawing marks this size for a 100mm wide PCB. Three T-slots (one in the top taking an M3 half-nut, two in the bottom taking M4 half-nuts) offer an alternative way to mount chassis or components that need conduction cooling. Two exterior T-slots on the bottom, also for M4 half-nuts, allow wall brackets, a belt attachment or a connection to another enclosure.

The purchased assembly includes the extrusion, 2 end plates, 2 bezels and 8 screws (#4 x 1/2 pan head), with a recommended cover screw torque of 2.5-3.5 lbf-in (30-40 cN-m). The 531611 is rated IP54, is RoHS and REACH compliant, ships shrink wrapped at 0.86 lbs (0.39 kg), and can be factory modified (milling, drilling, printing); solid models are available in STEP or IGES.