4 PCS Boston Valve, One Way Universal Air Valve for Inflatable Raft Kayak Pool Boat Inflatable Bed, Black This product ships based on the color or size of the main image on the product page. Material: The Boston inflation valve is made of high-quality ABS material, which is durable, corrosion-resistant and not easy to leak. Dimensions: Threaded portion base diameter 22mm (external) / 20mm (internal). The specific dimensions of the Boston valve can be seen in the second picture. Please check the size to make sure your valve plug will fit before purchasing. Application: Perfect for standard Boston valve replacement kits and most rafts, kayaks, pools, boats, inflatable beds and more. This valve is a one-way inflation valve suitable for rapid inflation. The air valve cap sealing design ensures leak-proof inflation. Shipping quantity: 4 pieces