The RP1120 is a water-tight general-purpose enclosure moulded in polycarbonate with an opaque lid, measuring 4.92 in x 3.35 in x 1.57 in (125 mm x 85 mm x 40 mm). It is intended for OEM engineers, electricians and integrators who need to mount printed circuit boards or components in a sealed box with a UL94 V-2 flame rating.

Hammond's series table and drawing list this number as the Off-White Polycarbonate opaque-lid version (the part page states Light Gray). The gasketed lid uses two-piece tongue and groove construction to keep out oil, dust and water, and its smooth recessed top area accepts a membrane, label or silkscreen.

This is the low 40 mm-high version of the 125 x 85 mm RP footprint, with 34.50 mm of inside height over a PC board area of up to 117 x 77 mm. The drawing gives overall dimensions of 125.50 mm [4.94 in] long, 85.50 mm [3.37 in] wide and 40.00 mm [1.57 in] high, with inside dimensions of 119.23 mm [4.69 in] long, 79.23 mm [3.12 in] wide and 34.50 mm [1.36 in] high. The series ordering table lists this size as 4.96 in (126 mm) x 3.39 in (86 mm) x 1.57 in (40 mm). Shipping weight is 0.35 lbs (0.16 kg).

Each purchased assembly includes the box, lid, string gasket, four PCB screws and four lid screws. The lid is secured with self-captivating M3.5 stainless steel machine screws threaded into corrosion resistant bushings for repeated assembly and disassembly; recommended torque is 43-50 ozf.in (30-35 cN.m). Internal mounting holes accept M3 self-tapping screws, and optional inner panels are available as STC113 (3 mm black ABS) or STA113 (1 mm metal).

The RP1120 is designed to meet IP65 and is RoHS and REACH compliant. Hammond cautions that acetone, ketones, thread-locking compounds, cutting fluids and strong solvents can damage ABS and polycarbonate enclosures, so check chemical compatibility before use.