Review on Topeak Presta Valve Extender by Richard Counts

I bought a pair of Zipp 808s and was very unhappy with the Zipp extensions that came with them. I did a little searching and found that this extension has some mixed reviews. They work uniquely in that they thread onto your existing Presta valve (no removable core required). The little piece of silver then actually unscrews the valve to open it for pumping. The point is (and maybe why the reviews are mixed) that I've had mixed results depending on the pump I used. My more expensive pump worked much better than the non-original one, so maybe my mileage is different. The pump should make a good seal with the end of this extension, but once it does I have no problem getting an accurate tire pressure reading and it was easy to pump up. I have 2 of these so I'm keeping them. worked hard all the time. The great thing is that I can use regular valved hoses instead of buying hoses with very long extensions. I just unscrew this extension well and then put the tube in the tire. This is more than enough for my Zipp 808s (which are very deep).