The MPB3 is a three-hole Type 12 mild steel miniature pushbutton enclosure in ANSI 61 gray from the MPB Series. It accepts three 22mm miniature oil tight pushbuttons, switches or pilot lights in a single column and protects them from dirt, dust, oil and water, making it a practical three-device station for machine and process controls. The RAL7035 light gray version is the MPB3LG.

The MPB3 is formed 16 gauge steel with smooth continuously welded seams. Welded brackets provide for enclosure mounting, captive cover screws thread into sealed wells, and an oil resistant gasket and adhesive seal the cover. A bonding stud on the door and grounding stud on the enclosure are provided. The cover and enclosure are phosphatized and powder coated ANSI 61 gray, and the cover is not hinged.

It measures 7.00 in (178 mm) high by 2.75 in (70 mm) wide by 3.50 in (89 mm) deep. The drawing shows 8.00 in overall height, a 7.31 x 3.06 in door, a 5.63 x 1.32 in door opening and 3.54 in inside depth. The 0.89 in pushbutton holes are spaced 1.88 in apart, and 0.25 in mounting holes are on 7.50 x 1.88 in spacing.

The series is rated UL 508A Type 12 and 13 and CSA Type 12 and 13, and complies with NEMA Type 12 and 13 and IEC 60529 IP54; appropriate components are required to maintain these standards. It carries UL File # E65324 and CSA Cert. # LR21001, is REACH and RoHS compliant, and ships boxed at 2.88 lb (1.31 kg).