Review on 6 Inch Dually Valve Stem Extenders - 2 Pack: Heavy Duty, Easy Installation for RV Tires, Truck, Motorhome, and More! by Brent Mosley

They look good and are well made, but they don't work! I have a Winnebago 32' Class C RV and installed it to replace the flex line so I can add TPMS. They're easy to install, but once installed I can't check tire pressure or fill a tire unless I add a flexible extension over a rigid extension. I have tried replacing the o-ring without installing the o-ring and have tried both extensions and have the same issue. I didn't have the leaks that other people complain about, but I expect if you pay the premium price you're getting something that actually works. I would definitely not recommend them to anyone.