Continental has long been renowned for their high quality tubular tires and they now offer an equally high quality valve extension for today's aero rims. These extensions are great because they fit inline on the valve between the valve core and existing valve stem. Rubber seals keep the air in but Teflon plumbers tape can be used to further strengthen the seal. A tool is included for valve core and extension removal/installation. They can be used with any tubular tire or tube with a removable valve core. Sold as a pair with one valve tool.