This is a special cylinder manufactured by Luxfer. It is a composite cylinder manufactured of both aluminum and fiberglass. It starts out as a standard
scuba 80 cuft cylinder. Hoop-wrapped fiberglass and resin is added to strengthen
the side walls. This allows for an increased service pressure to 4350 psi and a capacity of 106 cubic feet. This cylinder falls under DOT Special Permit 12479. Requirements of SP12479 is a hydro re-test each three years and a fifteen year service life. The inlet to this cylinder is unlike most other scuba cylinders, utilizing 7/8" x 14 UNF threads (a smaller hole). The choice of valves is restricted to a 300 bar DIN valve with the correct 7/8" x 14 UNF threads.