The 1591TBK is a black flame retardant ABS plastic enclosure from the 1591T size of the 1591 Series multipurpose project boxes with card guides. Measuring 4.72 x 3.16 x 2.32 in (120 x 80 x 59 mm), it gives electronics designers, OEM engineers and hobbyists a compact housing for printed circuit boards that stand vertically in molded guides. It appears in the series ordering table under Flame Retardant ABS Enclosures without mounting flanges, with a nominal size of 4.72 x 3.15 x 2.32 in.

The box is molded from easy-to-machine flame retardant ABS carrying a UL94 V-0 flammability rating. Lap joint construction between box and lid protects against dust and splashing water, and the enclosure is designed to meet IP54. Because it is a black enclosure, it ships with black lid screws.

Inside, the usable space is 113.54 x 73.74 x 54.80 mm (4.470 x 2.903 x 2.157 in). Card guides are molded into all side walls and accept 1.5 mm (0.062 in) thick boards, with a guide height of 49.80 mm (1.961 in). For horizontal board mounting, 1591Z card adaptors are sold separately in packs of 6, 50 or 100.

The lid fastens with four M3 x 10 mm Phillips machine screws that thread into pre-installed brass inserts, so it can be opened and closed repeatedly; the recommended torque is 35.5-42.5 ozf.in (25-30 cN.m). The purchased assembly includes box, lid, 4 cover screws and the brass inserts. A clear polycarbonate replacement lid, 1591TC, is available, and the part is RoHS and REACH compliant with a shipping weight of 0.29 lbs (0.13 kg).