High Quality – The air valve screw cap is made of high-quality high-density PVC plastic, offering good performance, long life, strong corrosion resistance, and durability. Cap Design – The air valve cap features a sealed design to ensure anti-leak inflation. The upper threaded part measures 22mm (outer) / 17mm (inner), and the lower threaded part measures 22mm (outer) / 20mm (inner). Please check the size to ensure compatibility with your valve before purchase. Leakproof Design – The inflatable air valve replacement screw is designed to create a secure seal. A rubber pad at the bottom of the air plug ensures a tight fit against the valve edge after inflation, effectively preventing leaks and providing reliable protection. Quick Inflation and Deflation – This spiral air plug fits piston holes of approximately 22mm (0.78 inches), allowing for fast inflation and deflation, saving time during use. Application – This standard Boston valve replacement set is compatible with most kayaks, inflatable boats, rafts, and rubber dinghies. It is not universal; please measure your existing valve size before purchasing. Note 1. Product dimensions are measured manually; a 2mm variation may occur due to different measurement methods and tools. 2. Images are taken of the actual product, but slight color differences may appear due to lighting, photography, screen settings, or personal color perception. The actual product color should be considered definitive.