B-Line Eaton series Type 3/3R junction boxes, 6" height, 4" length, 4" width, 3 and 12, Screw cover, WPSC enclosure, Surface mount, Small single door

Six inches high, four inches wide and four inches deep, which is where the 644 designation comes from. That 4 inch depth is the number to check first: deep enough for splices, terminal blocks or a small relay, but tight for anything with a DIN rail stack or a device that projects off a back panel.

Surface mount with external mounting feet, so the fasteners go outside the box and nothing penetrates the sealed enclosure body. That is what keeps the 3R rating intact. At 2.7 lb empty it hangs off unistrut, a pole bracket or masonry anchors without special support.

Screw cover, flanged, not hinged. You back out the gasketed screws and lift the cover off completely. Fine for a junction or pull point you rarely open; if the box gets opened routinely for troubleshooting, a hinged-door enclosure is the easier choice because a loose cover has to be held while you work.

Carbon steel at 16 gauge, painted ANSI 61 grey. That is a standard industrial paint finish over steel, suitable for general outdoor and plant environments. For washdown, coastal salt air or chemical exposure, stainless or fiberglass is the better call, since painted carbon steel will corrode where the finish gets scratched.

The WPSC series ships as a blank enclosure, with no knockouts, so you drill or punch conduit entries where your run needs them. Standard practice on a 3R box is to keep entries on the bottom or lower sides and use rated watertight hubs or fittings, since an unsealed top penetration voids the rain-tight performance.

It is built to UL 50, the standard covering enclosures for electrical equipment, and it is manufactured in the United States. That combination matters on specs that call for a UL 50 enclosure or carry domestic sourcing requirements on a government or institutional job.

Yes for a straight-through or simple pull. With a 6 x 4 x 4 inch body you have six inches between opposite ends on the long axis, which handles straight pulls on small trade sizes and gives room for a few wirenut splices. For angle or U pulls on larger conduit, size the box by NEC pull box rules rather than by fit, since those require a multiple of the largest raceway diameter.

It covers the small end of a standard enclosure lineup: ANSI 61 grey painted steel, surface mount on external feet, screw cover, rated NEMA 3 and 12 so one part number serves both an outdoor wall and an indoor dusty area. The 6 x 4 x 4 inch size handles device boxes, splice points and small controls. Larger openings in the same series carry the same finish and cover style, so a facility spec stays visually and functionally consistent as sizes step up.