Zipp 27mm Valve Extender for Threaded Presta Valves - Durable Black Alloy with Knurled Grip & 3mm Hex for Secure Seal & Easy Pumping

This doesn’t work. I have deep wheels and needed a valve extender. Not only is this not a normal valve extender, but when you use it, air escapes as you pump, so it’s impossible to properly inflate your tires. Do not buy this product; it’s garbage.

I have shallow aero times. Regular valves reach through them just about, but not enough to get a pump fitting onto. All the other valve extenders seem to be designed to be fastened to tubes semi-permanently, which: 1) need PTFE tape to get a goof seal, 2) degrading over time if screwed on and off different tubes, 3) need to put on to all your spare tubes before a ride, and 4) have to be left on, sticking out inside your rim. These extenders, on the otherhand, can be screwed on and off many times without degradation, and create an adequate seal when hand-tightened without needing PTFE tape. The only issue I have is that the barb, which helps fasten the attachement to the pump is really aggressive, making it difficult to remocve it from the pump. I hactually leave it attached to the pump and screw it on and off the tube with it connected like this. I also keep one in my saddle bag.