The 1591XXUGY is a light gray, flame retardant ABS project box from the 1591XX multi-purpose series, measuring 4.86 in x 4.86 in x 2.25 in (123 mm x 123 mm x 57 mm). It is intended for engineers and builders mounting a printed circuit board horizontally in a compact, near-square housing.

This standard version is molded from easy-to-machine ABS with a UL94 V-0 flammability rating and is designed to meet IP54 for protection against dust and splashing water. Four M3-0.5 x 10 mm Phillips machine screws thread into installed brass inserts to hold the lid, so the enclosure tolerates repeated assembly and disassembly. Gray enclosures include nickel plated screws, and the recommended torque is 43-50 ozf.in (30-35 cN.m).

Internal space is 115.66 mm long, 115.66 mm wide and 55.40 mm high, with a 2.00 mm wall. The internal sides are smooth to simplify fitting connectors. Integral PC board posts in both the box and lid accept #4 x 1/4" self-tapping screws (not included), and boards up to 114 mm x 114 mm are listed as the maximum size.

The 1591XXUGY has no mounting flange, but matching ABS mounting flanges are sold separately as 1591FUBK (black) and 1591FUGY (grey). It is RoHS and REACH compliant, ships in shrink wrap, and can be factory modified with milling, drilling or printing.