If our image makes it look as if the Stan's No Tubes Tubeless Rim Strip is a tube, rest assured, it isn't. The Stan's Rim Strip has a Presta valve stem built right into it. It has a removable core -- not only good for replacing damaged valves but also for applying sealant. Stan's No Tubes Tubeless Rim Strips should fit most standard 26in diameter MTB rims that are 21. 5 to 25mm wide. They work with Mavic's 223, 221, 317, 517, 519, 717 rims, and 719, Sun's 0 XC, UFO, and Sub4, as well as DT's 4. 1, and most other non-Freeride, non-AM, non-DH rims.