IST Aluminum Backplate The back plate is the heart of a technical buoyancy compensator. It provides the vital connection between a diver and his scuba. Individually press-formed and all edges de-burred, DOLPHIN TECH back plates have 5cm (2") slots for the harness and crotch strap as well as 10 perimeter holes for attaching additional equipment such as stage bottles and canister torch. There are 3 sets of tank mounting holes along the plate’s center line, giving the diving easier option to fine tune tank to torso position.