This tool is mainly used for filling oxygen into your oxygen cylinder. The pressure gauge and hose are designed to give you a safer experience. If you are looking for this product, come and have a try, it will not let you down. Features: Portable Size: This scubas diving tanks refill adapter set has a portable size and is easy to store, you can put it into your tool bags to carry. Easy to Install: The install and removal process of this product is very convenient. No other tools are required. The design of this product allows you to fill your tanks quickly, which is convenient for outdoor use. Compatibility: 8mm fill valves size can be compatible with most standard scubas valves, and has a wide application. Preferred Material: The adapter is made of aluminium alloy material and the hose outside with steel wire, giving you a safer using experience. Pressure Meter&Hoses: The pressure gauge and hose are designed to give you a safer experience, you can notice changes in pressure at any time. Specifications: Material: aluminium alloy Thread: 8mm Working pressure: 30MPA Hose length: about 500mm Item size: 135 * 62 * 23mm / 5.3 * 2.4 * 0.9in Package size: 170 * 120 * 55mm / 6.7 * 4.7 * 2.2in Package weight: 500g / 1.1lb Packing list: 1 * Scubas Adapter with Hose