The Zipp Tangente butyl tubes are designed to meet the needs of a new era of road riding that includes adventures aboard wider tires. The tube's 0.60mm thickness is optimized for durability.37mm valve stem lengthLightweight aluminum valve body with removable Presta valve coreFor use with Zipp Tangente Aluminum Knurled Valve Extender0.60mm thick to optimize durabilityWhen installing Zipp Tangente tubes (37mm valve stem) on Zipp wheels the following valve extender is recommended: PU9911 27mm (1 gram) for 303 model wheels PU9912 41mm (2 g.) for 404 models PU9913 65mm (4 g.) for 808 models PU9914 91mm (6 g.) for 1080 models