The 1591SFLBK is a black flame retardant ABS enclosure in the 1591S size with wall mounting flanges molded into the lid. The 4.33 x 3.24 x 1.73 in (110 x 82 x 44 mm) box is aimed at electronics builders, OEM designers and installers who want a small PCB housing that fastens directly to a wall or panel.

With the flanged lid the overall length is 135.20 mm (5.323 in), mounting holes are 124.20 mm (4.890 in) apart and overall height is 43.80 mm (1.724 in). The lid also accepts #4 self-tapping screws for mounting a circuit board to it; 1593ATS50 and 1593ATS100 #4 x 1/4 in (6.4 mm) screws are listed for this.

The enclosure is molded from flame retardant ABS rated UL94 V-0, with lap joint construction to protect against dust and splashing water and a design intended to meet IP54. Because it is a black enclosure, it ships with black lid screws. Inside there is 103.77 x 75.87 x 39.90 mm (4.085 x 2.987 x 1.571 in) of space, and card guides in all side walls accept 1.5 mm (0.062 in) boards, 34.90 mm (1.374 in) high.

Four M3 x 10 mm Phillips machine screws thread into pre-installed brass inserts to close the box; the recommended torque is 35.5-42.5 ozf.in (25-30 cN.m). Box, lid, 4 cover screws and the brass inserts are included. The part is RoHS and REACH compliant and has a shipping weight of 0.23 lbs (0.10 kg).