Characteristics: It comes in three parts: one inner part, one outer part and valve cap. Fits most inflatables, river rafts and kayaks. Easy to inflate and deflate. Double leak protection. Excellent air leakage performance. A great accessory for sailing enthusiasts. Technical data: Material: PVC Color: Gray Upper Outer Diameter: Approx. 6.5 cm / 2.5 inch Bottom Outer Diameter: Approx. 4.2 cm / 1.6 '' Height: Approx. 5 cm Weight: Approx. 85g How to use: Method 1: Inflate the air when the spring in the center of the valve does not pop out (only inhale but not pop out) Advantages: After filling the air, pull out the inflation tube, the air nozzle shrapnel will close automatically and there will be no air leakage Cons: slow inflation speed, long time, there may be abnormal noise due to gas pushing shrapnel Method 2: Turn the operating lever in the center of the gas nozzle and the second shard will be fully opened (inlet and outlet) Advantages: fast inflation speed, short time, no abnormal noise; Cons: When fully charged, when the inflation tube is pulled out, some air will leak as the air nozzle is fully open until the control lever is closed in the center of the manually rotating air nozzle Either way, after inflating the air, the cap of the air nozzle and the air nozzle must be tightly tightened to prevent air leakage Packing list: 1 x boat air valve Note: After inflation, tighten the valve and valve cap in case of air leakage.