Whether it’s filled with regular filtered air or enriched air nitrox (higher oxygen and lower nitrogen content) or trimix (three-gas combination) for technical diving, a scuba tank is one of the most important pieces of gear.

Cylinders are made of either steel or aluminum alloy, although other composites are possible.

  • Steel cylinders are tough and resistant to external damage, but need proper care to avoid internal rust. They are negatively buoyant. The highest capacity cylinders are steel.
  • Aluminum cylinders are more susceptible to external dents, dings and scratches than steel cylinders, but better resist internal corrosion.