The Hammond 1550B is a rugged diecast aluminum electronic instrument enclosure from the 1550 Series, a slim 115 x 64 mm box at the low 30 mm table height; the 1550D shares this footprint at 55 mm. It suits electronics designers, OEM engineers and hobbyists who need a tough metal project box that is still easy to machine for connectors, switches and controls.

The body and lid are die-cast aluminum alloy, in a natural vibra finish that leaves a smooth surface with no sharp edges. Lap joint construction gives protection against access of dust and splashing water, and the part is rated IP54 as supplied (without a gasket). The lid is secured with M3.5 x 0.6 x 12 mm long stainless steel Philips head machine screws into factory tapped holes.

The series table lists the 1550B at 4.53 in (115 mm) long, 2.52 in (64 mm) wide and 1.18 in (30 mm) high, with dimensions including the 4 mm (0.16 in) lid; the part page lists 4.51 in x 2.52 in x 1.02 in (115 mm x 64 mm x 26 mm). Inside, the drawing gives a box length of 110.66 mm [4.36 in], width of 60.16 mm [2.37 in] and height of 27.10 mm [1.07 in]. There are no internal ribs, so connectors install without interference or extra milling, and the low side wall draft angle (2° less) eases PC board mounting.

To seal to IP66, add the 1550BEGASKET EVA foam gasket kit, or upgrade to IP67 with the 1550BSGASKET silicone kit; both are sold as pairs and install on the lid with adhesive backing. The same size is offered as 1550BBK (black), and as 1550WB / 1550WBBK with the IP66 gasket included. Replacement lid screws are 1550MS100 (100 pack), with tamper-resistant 1550MS50T (50 pack) and driver bit SCDRIVET15-2.