The Caffe Tubeless Presta Valve pack includes two tubeless valves and one valve-core tool. Thanks to a removable valve core design, most types of presta valve extensions (if needed) and can be used and the valve core can be replaced. The rubber base ensures a snug fit. To install, just hand-tighten the lock nut (that compresses the rubber base against the rim). This design eliminates the need for easy-to-loose o-rings.