The PJ664R is a compact Type 4X junction box in fiberglass reinforced polyester with a raised, lift-off solid cover. It measures 6.10 x 6.10 x 4.18 in (155 x 155 x 106 mm) and is intended for instrument enclosures, electrical junction boxes, terminal wiring and electric, hydraulic or pneumatic control housings where equipment may be hosed down, very wet, hot or in highly corrosive surroundings. As the solid lift-off version, it is marked in the series table as meeting Type 6P.

Box and cover are compression molded fiberglass reinforced polyester in gray, with enhanced UV inhibitors against outdoor weathering, and are easily punched, cut or drilled. The cover is fastened by four stainless steel captive cover screws with retaining O-rings, threading into #10-32 brass inserts. A closed cell neoprene gasket, described in the series as captive and oil resistant, provides a positive seal.

For mounting equipment, four #10-32 brass inserts with plated carbon steel screws accept the optional 14R0505 inner panel, 4.88 x 4.88 in (124 x 124 mm), in white powder coated steel, unfinished aluminum or fiberglass; mounting hardware is included. Four stainless steel mounting feet attach to rear brass inserts for wall installation.

The PJ664R is UL 508A listed Type 1, 2, 3, 4, 4X, 12 and 13, cUL listed to those types per CSA 22.2 No. 94, and complies with IEC 60529 IP66. It is rated for 130°C to -40°C (266°F to -40°F), has a 6.78 J (5 ft/lb) impact index, is RoHS and REACH compliant, and ships at 3 lbs (1.36 kg).