Part 1551KRGY is the light gray (RAL 7035) version of the 1551K miniature hand held enclosure supplied with a key ring kit; the manufacturer describes it as "1551KGY with key ring". It is aimed at designers who need a small, carry-anywhere case for a compact circuit board, or a neat potting box that hangs on a key ring.

• Outside size: 80 x 40 x 20 mm (3.15 x 1.57 x 0.79 in), depth including lid
• Inside: 74.73 mm long, 34.73 mm wide, 16.00 mm high
• Maximum P.C. board: 74.00 x 34.00 mm (2.91 x 1.34 in)
• Wall thickness: 2 mm (0.08 in)

The enclosure is molded in general purpose ABS plastic rated UL94 HB. Lap joint construction between box and lid helps keep out dust and splashing water, and the design is intended to meet IP54. For the key ring, the enclosure comes predrilled in the narrow side.

Inside, molded PC board standoffs take #2 x 3/16 in self-tapping screws (sold separately as 1551ATS50 or 1551ATS100). The lid closes with the 2 included #4 x 1/2 in self-tapping screws, which are nickel plated to match grey enclosures; recommended torque is 35-43 ozf.in (25-30 cN.m).

The 1551KRGY is RoHS and REACH compliant, ships bagged at 0.06 lbs (0.03 kg), and has a black twin, 1551KRBK.