Stan8242s tubeless system converts your existing wheel set to tubeless it allows you to use either standard or tubeless tyres saving hundreds of dollars and weight over purchasing other tubeless systems fits most standard mountain bike rims mavic 221 317 517 519 223 and sun 0 xc ufo sub4 etc also fits bontrager 298242er disc rimsnote rim strips feature presta valve stemsthis kit includes two molded rim strips with presta removable valve cores one pint of tire sealant with a 60g