Easy to use Air pressure gauge that works on almost all valves (ex. boston) and reads pressures of 0 – 20 psi. Most inflatable manufacturers have a recommended P.S.I… do you know what yours is? Now you can read it accurately and easily. It will help protect your investment and you will be surprised to see how much better your craft will perform when inflated properly. Works wtih Leafield, Halkey-Roberts, Summit and most knock-off valves too!