Greg Flanagan first invented the metal backplate using aluminum in 1979 for North Florida cave divers. He realized that a back-mounted buoyancy system gives a diver natural balance in the water, due to the diver's center of gravity (tanks) being surrounded by the center of buoyancy (BC wings). Plus, the diver gains a clean chest area with room for gear attachment points on the harness. Bill Hogarth Main went on to popularize the backplate and harness and dive purists who follow the DIR philosophy have come to embrace what is known today as the "Hogarthian Rig." Dive Rite began manufacturing backplates for the public in 1984 and pioneered 11-inch on center bolt spacing creating an industry standard that is still followed today. Northeastern wreck divers adapted the concept and began using a stainless steel backplate; at six pounds in weight, it is ideal to counterbalance buoyancy characteristics of thick drysuit exposure protection. Eleven-inch on center holes accommodate standard double tank bolt kits. Holes along the perimeter of the plate allow for mounting lights, pony bottles, lift bags and other accessories. One-inch and 2-inch slots permit diver's choice of crotch straps. Two 3/8-inch slots along the bottom are designed to fit screws for attaching lift bag sleeves, sidemount butt plates or other accessories. Two-inch slots along the center allow single-tank divers to use cam straps without a single tank adaptor. All edges are deburred to eliminate sharp edges and prevent abrasion to harness webbing. Grade 304 stainless steel is passivated, which prevents oxidation. Made in the U.S.A.