Material: The air valve cap made of quality high dense plastic, sturdy, anti-corrosion and durable. Quickly & Deflation: The air valve cap can fit into the bottom 20 mm / 0.78 inch hole, boston valve to help quicker and deflation. Rubber Pad: The bottom of the air plug has a rubber mat which can prevent leaks more effectively, give you protection.One-way valve, quickly inflated. design: the great design with a valve cap ensures anti-leak ,two way air valve, which is more easier to inflate quickly. Widely Use: Fits most inflatable boat, raft, rubber dinghy, etc. measure the valve size of the inflatable boat in advance purchasing. Colour:black Material:plastic Package Contents: 4 * Boston Valve 4 * gasket Only the above package content, other products are not included. Note: Light 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 +/- 1-3cm.