The Stan's No Tubes custom 44mm Presta valve stems converts most 700c rims to tubeless when used with NoTubes 21mm yellow tape and sealant (sold separately). This valve will seal most existing rims that have an inner valve stem hole of 6-8mm. Removable valve core allows easier application of tire sealant. (Rims with no inner spoke holes do not require the yellow spoke tape. SOLD IN PAIRS ONLY !