FD yellow glass-filled polyester box, corrosion-resistant. (2) 12.7 mm threaded knock-out openings. Boxes molded of high-strength, non-conductive, glass filled polyester. All metal hardware on boxes made from Stainless Steel to provide stable anchor points and corrosion resistance. Entry/exit points pre-threaded with knock-outs for quick, flexible installation. Grounding wires included and pre-installed to save time on installation.