The Zipp Tangente butyl road inner tube is designed to improve rotational stability by decreasing rotational mass at the valve body.It features a lightweight (weighing 89 grams without a valve extender) aluminium Presta-valve body, 37mm length with a removable valve core. The aluminium valve body saves weight, allowing for a tube that is .85mm thick to optimise durability. Extenders also are available in lengths for each Zipp wheel along with a handy wrench set. Tangente Tube 700c Butyl w/ Aluminum Presta Valve 37mm (use with Tangente Valve Extender and Wrench)