Material: The air valve cap is made of high-quality, high-density plastic, which is sturdy, anti-corrosion, and durable. Quickly Inflation & Deflation: The air valve cap can fit into the bottom 20mm / 0.78 inch hole, Boston valve helps with quicker inflation and deflation. Rubber Pad: The bottom of the air plug has a rubber pad that can prevent leaks more effectively and provide protection. One-way inflation valve allows for quick inflation. Nice design: The great design with a valve cap ensures anti-leak inflation, two-way air valve, making it easier to inflate quickly. Widely Use: Fits most inflatable boats, rafts, rubber dinghies, etc. Please measure the valve size of the inflatable boat in advance before purchasing. Color: Black Material: Plastic Package Contents: 4 x Boston Valve, 4 x gasket Only the above package content is included; other products are not included. Note: Light and different displays may cause the color of the item in the picture to appear slightly different from the real thing. Measurement allows for an error of +/- 1-3cm.