I bought these because the first question and answer was if they are schrader valves and the answer was yes. This is NOT accurate. Instead of a Schrader rod, these extensions have a ball valve on the end. It is very difficult to install and make a good enough connection to get a pressure reading. Haven't tried them with the chuck handle on my air compressor, but I hope it works and makes it more useful. But I've tried checking tire pressure with a regular gauge and had trouble getting it just enough to get a solid reading.