The 1591UBK is the black, flame retardant 1591 Series enclosure in the square 120 x 120 x 59 mm (4.72 x 4.72 x 2.32 in) size, without mounting flanges. It gives electronics designers and integrators a roomy footprint for vertically mounted circuit boards in a compact height.

The box is molded from easy-to-machine flame retardant ABS carrying UL94 V-0. Card guides in all side walls accept 1.5 mm (0.062") boards, and lap joint construction helps keep out dust and splashing water, with the enclosure designed to meet IP54.

Overall drawing dimensions are 120.00 x 120.00 x 59.00 mm; inside, the cavity is 113.54 x 113.54 x 54.90 mm with 49.90 mm high guides. The lid is secured with M3 x 10 mm Phillips machine screws threaded into pre-installed brass inserts, suited to repeated assembly and disassembly; black enclosures come with black screws. Recommended torque is 35.5–42.5 ozf.in (25–30 cN.m).

The 1591UBK includes box, lid, 4 cover screws and brass inserts, ships in shrink wrap at 0.36 lbs (0.16 kg), and is RoHS and REACH compliant. The 1591UC clear lid fits this size.