The 1551UFLBK is a black general purpose ABS plastic miniature enclosure with an integrated mounting flange molded into the lid. It measures 100 x 40 x 20 mm (3.94 x 1.57 x 0.79 in) excluding the flange, and is intended for OEM engineers and electronics builders who need to house a small printed circuit board or use the box as a potting shell, then fix it to a wall or panel, or suspend it with a tie wrap.

Its 100 x 40 mm footprint is the longest in the 1551 range, and the 20 mm depth including lid gives more head-room for components on a long, narrow board up to 94 x 34 mm. Inside, the box measures 96.00 x 36.00 mm [3.78 x 1.42 in], and the drawing gives a maximum PC board size of 94.04 x 34.04 mm [3.70 x 1.34 in]. PC board standoffs are molded into the interior and accept #2 self-tapping screws; the recommended board screw is #2 x 3/16", which is not included.

With the flange, overall length grows to 116.30 mm [4.58 in]. Flanged versions of the 1551 series are made in black or grey only, and this one is molded in black (RAL 9011). The lid closes with four #4 x 1/2" self-tapping screws, black plated to match the enclosure, with a recommended torque of 35-43 ozf.in (25-30 cN.m).

Walls are 2 mm (0.08") thick and the lap joint between box and lid protects against dust and splashing water; the enclosure is designed to meet IP54 and carries a UL94 HB flame rating. The 1551UFLBK is RoHS and REACH compliant, ships in a bag with the box, lid and 4 cover screws, and has a shipping weight of 0.07 lbs (0.03 kg). Some chemicals, such as acetone, thread-locking compounds and cutting fluid, can damage ABS, so check compatibility before use.