The Hollis Stainless Steel Backplate is stamped out of Electro Polished 316 Stainless Steel and all holes, slots, and edges have been smoothed and de-burred to prevent edges that may be abrasive to the diver or your gear. The Hollis Stainless Steel Backplate is specifically designed and engineered to have less arch and bend parallel to the spine to keep the tank is closer to the body eliminating any unwanted gaps and maintaining a more streamlined system with less drag. The Hollis Stainless Steel Backplate is designed to be used with double or single mount cylinder setups. If you are using a single you will need the use of an STA (Single Tank Adapter). Hollis Stainless Steel Backplates are cut with two slots for the crotch strap one at 1″ (2.5 cm) and another at 2″ (5 cm) making it the divers choice which to use. The Hollis Stainless Steel Backplate weighs approximately 5.5 lbs (2.5 kg).