Stability and durability, the CO2 cylinder refill connector is made of high-level brass, stable characteristic, maximum durability. Easy to use, the CO2 tank adapter is easy to screw empty CO2 cylinders (not included) into the adapter. and convenient Easy to use and store, easy to carry. A simple and inexpensive way to refill your own cylinders at a fraction of the cost of refills at your local store. You can enjoy healthy carbonated water every day at a low price. No gas leakage when connected to the cylinder, good sealing performance. Model: TR21-4 to W21.8-14 with watch Weight: 197g Height: 47mm Gauge pressure: 2000psi, bottom gauge Material: Brass Color: Copper Package Contents: 1 * Air Valve 3 * Transparent Spacers 1 * White Gasket 4 * Rubber Rings Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/