Our battery carrier strap makes it a breeze to use a canister light with an adjustable harness. On a backplate with an adjustable harness (on the right side) the canister and the buckle holding the canister may interfere with the adjustable harness. This battery carrier strap attaches to the unused slot in the backplate. It features a separate piece of stiff webbing to hold the canister and a special belt buckle. The battery carrier belt buckle slides onto the right waist belt and does not interfere with the adjustable harness.