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 aluminum Presta-valve body, 37 mm length with a removable valve core. Tubes are 700c x 19-23mm, weighing 89 grams without a valve extender. The aluminum valve body saves weight, allowing us to make a tube that is .85mm thick to optimize durability. Extenders also are available in lengths for each Zipp wheel along with a handy wrench set.