The 21mm width rim tape from Stan's NoTubes provides full coverage from bead to bead on narrower rims like your basic road rim or narrow mountain rims. It will cover the spoke holes and eyelets on just about any road or mountain rim to provide proper sealing if you plan on running a tubeless set up. The tape also doubles as a standard rim strip. The tape roll is 10 yards long which is ample for a 2 pair of wheels and 21mm in width. One side is semi-adhesive and has some stretch to it. The material is quite robust and should give you any issues during install and when in use.