This is the OMS 2 lb Aluminum Back Plate BP-020 for Single to Double Tank System It Features: OMS Quality! Durable Aluminum structure Aluminum plate is Hard Coat Anodized Includes the follwing slots: 1 and 2" width Crotch Strap, (2) Cam Band, and a bottom slot to accommodate band bolts that are slightly off 11" On Center Engineered to fit closer to the cylinders preventing "Gapeosis", creating a "tighter profile" and as a result reduces drag OMS&';s superior deburring process eliminates back plate sharp edges, and prevents abrasion and cuts to webbing and BC&';s A fantastic addition to your custom built BC! "