PRESTA VALVE STEM: Removable valve core makes adding sealant easy. HIGH-QUALITY MATERIAL: Made with aluminum, these Presta tubeless valve stems are durable and versatile. FITS MOST RIMS: Compatible for almost any tubeless bike rim sizes,including both road and mountain bikes. PRODUCT MEASUREMENTS: Includes two 35-mm aluminum Presta valves with removable cores and rubber caps. GENUINE STAN'S PRODUCT: When you buy this product, you will receive an authentic Stan's NoTubes item.