This Back Pack Design is one of the original styles manufactured. Harness, Standard Hard-Plastic Pack with 2" (5.1 cm) Nylon Webbing Assembly, Soft Tank Band and Cam Buckle is Easy to Duff and Don. Waist and Shoulder Quick-Release Buckles are made from Corrosion Resistance Steel for durability and long life. Tank Back Pack is a great item for pool cleaning or working under a boat. Cylinder Cam Band is adjustable for use with 6.9" to 8.0" (17.5 to 20.3 cm) Cylinder Diameters.