Review on Alloy Bicycle Tube Presta Valve Extenders (2 Pack) 20mm-60mm for MBP Bikes by Imran Roach

First, there are a lot of 1 star reviews from idiots who don't understand the product they are buying. No, you can't screw it onto the valve core because (most) valve expanders work differently! If you know what you are buying, the product will work well. In my case there are no leaks even without lube or teflon tape. When ordering, please note that the specified size only refers to the visible part of the extension. Contrary to the product description, the total length including the threaded part is greater than the nominal size. See image: Zipp extension nominal 27mm vs nominal 30mm MBP; the actual difference in length is almost 12 mm. Finally, remember that you will not receive 4 different sized extensions as shown in the picture; what you get are 2 that are the same length.