Bike Master Performance Motorcycle Tube The Bike Master Performance Tubes excel in durability and design, crafted with natural rubber for enhanced wear, flexibility, and elasticity when compared to synthetic rubber options. This material choice not only improves puncture resistance and reduces the likelihood of tearing when heated, but it also offers a more economical option. A robust valve stem complements the high-quality construction, ensuring a seamless and worry-free riding experience. Features: Tr-4 / TR-6Straight standard metal stem type (8mm dia) Tr-4 uses an oval-shaped rubber transition from valve to the body of the inner tube Tr-6 uses a round rubber transition Naturalrubber tubes, with heavy duty valves Center metal valve unless otherwise noted Offset valve stem (where noted) usestraight valve stem Tubes are sold each Note : Tr-4 and Tr-6 valve stem styles can be used interchangeably.