The 40 Cubic Foot (5.7 liters) Aluminum Tank is a small compact cylinder that is great for use as a stage bottle for decompression and safety stop use. It is also commonly used by technical divers as a bailout bottle. The cylinder is a 3000 psi (200 bars) service pressure tank measuring 24.8" (63 cm) tall, with a 5.3" (13.46 cm) diameter. The cylinder weighs 14.9 lbs. (6.76 kg) is negative 0.7 lbs. (317.5 g) when full in salt water and is positively buoyant 2.4 lbs. (1.1 kg) when empty. The cylinder comes with a Pro Valve. The Pro Valve is one of the highest flow cylinder valves available today and is also a convertible valve. Whether you dive Yoke or DIN regulators this valve will work for both. Valve has easily removed 200 bar (3000 psi) DIN insert to convert the valve for use with DIN regulators. Valve has a heavy duty deign with a smooth operating mechanism and multi-ported burst disc plug for added safety. Aluminum cylinders unlike steel cylinders don't rust, they oxidize. The oxidization of aluminum forms a protective coat that hinders the continuation of corrosion making aluminum cylinders less likely to be condemned due to excessive corrosion. When shipped the tanks valves will be removed and the tank will require re-inspection before being filled. Note: All cylinders are nitrox ready up to 23.5%and meet certificated specifications of the US Department of Transportation (DOT) with DOT-3AL specification and Transport Canada Safety and Security (TC) with TC-3ALM specifications. Purchasers should check with other country requirements to know if the cylinders are certified for use in that country. .