This simple yet effective design allows you to extend your valve shaft by 30mm while still having an intact valve. First, you must make sure you have a standard valve core that is removable. Not all tubes have removeable cores, and some tubular tires use proprietary systems. To install, remove your existing valve core, thread the core into the end of the extender, then thread your extender into the existing valve. It's that simple Continental even provides the small tool you need.
This is a true, natural extension of your valve. No more always-open valves as used by other designs that just thread over an existing valve stem keeping the pressure valve open. No poor quality, ill-fitting threads that leak air at high pressure. Easy to install and reliable in the real world.