These extenders are only compatible with clincher tubes and tubular tires with removable valve cores.
An advantage of Vittoria's extender is that it's actually inserted between the valve body and valve itself. The original Presta valve gets unthreaded, the extender is inserted, and the original valve gets threaded into the tip of the extender. This makes for easy inflation, tyre pressure adjustments or deflation because the pump attaches to the original valve, not the extension.
• 2 Valve Extensions
• Weight: 4g
• Includes: tool to remove and install valve core and a Teflon sealing band
• Length: 30mm