The characteristic difference between this and the basic harness, is that a rigid or flexible backplate is added between the cylinder and the harness straps. The cylinder is attached to the backplate by metal or webbing straps, and the harness straps are attached to the backplate. In other respects the system is similar to the basic harness. Methods of fixing the cylinder include metal clamping bands, secured by bolts or lever operated clamps, or webbing straps, usually secured by cam buckles.