Works as intended. You attach it to the tire valve and the white end pops out to indicate PSI. Yes, it's analogue, but very accurate (my TPMS in the car confirms this device when I get back in the car). A few years ago I had a digital pressure gauge that was no longer accurate. It's cheap, dated, easy to use, and good for checking tire pressure at the gas station when the weather gets cold and you need to inflate.