The 1551UTBU is a translucent blue general purpose ABS plastic miniature hand held enclosure measuring 100 x 40 x 20 mm (3.94 x 1.57 x 0.79 in) including the lid. It is aimed at OEM engineers, hobbyists and product designers who need a compact housing for a small printed circuit board or a ready-made box for potting electronics.

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.

The box is molded in translucent blue ABS and the lid is held by four #4 x 1/2" self-tapping screws, black plated to match. Recommended screw torque is 35-43 ozf.in (25-30 cN.m). The same size is offered as 1551UBK, 1551UGY in the other colours.

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 1551UTBU is RoHS and REACH compliant, ships in a bag with the box, lid and 4 cover screws, and has a shipping weight of 0.06 lbs (0.03 kg). Some chemicals, such as acetone, thread-locking compounds and cutting fluid, can damage ABS, so check compatibility before use.