The 1591VBK is a black flame retardant ABS plastic enclosure measuring 120 x 120 x 94 mm (4.72 x 4.72 x 3.7 in), built for electronics designers, OEM engineers and hobbyists who need a compact, square project box with integral card guides for vertically mounted printed circuit boards.

It is molded from easy-to-machine flame retardant ABS carrying a UL94 V-0 flammability rating and is designed to meet IP54. Lap joint construction between box and lid provides protection against the access of dust and splashing water. Black enclosures in the 1591 series ship with black lid screws, so the finished case has a uniform dark appearance on a panel, bench or equipment shelf.

Inside, the box offers 113.23 x 113.23 mm (4.458 x 4.458 in) of length and width and 89.90 mm (3.539 in) of height. Card guides molded into all side walls accept 1.5 mm (0.062 in) thick boards, with a guide height of 84.90 mm (3.343 in) and a 2.06 mm (0.081 in) slot width. Where horizontal board mounting is preferred, 1591Z PC board card adaptors can be fitted.

The purchased assembly includes the box, lid, four cover screws and pre-installed brass inserts. The lid is secured with M3 x 10 mm Phillips machine screws threaded into integral brass bushings, which suits applications needing repeated assembly and disassembly; the recommended torque is 35.5-42.5 ozf.in (25-30 cN.m). A clear polycarbonate lid, 1591VC, is available for this size, and the 1591VBK can be factory modified by milling, drilling or printing.