Far superior to ordinary gauges, this commercial grade tire gauge uses a friction-free bourdon tube (long used by scientific instrument manufacturers as a dependable means of measuring pressure). The geared, solid brass precision movement is exceptionally accurate and is unaffected by changes in temperature, humidity or altitude. We've used this same gauge for over 15 years on everything from bicycles and autos to aircraft. The 12 in. flexible extension hose facilitates easy readings. A special bleeder valve releases excess air from the tire while monitoring tire pressure. The heavy steel case has a 2 in. dia. dial with an unbreakable crystal. The entire gauge is encased in a rubber, shock-absorbing cover to protect it if dropped. Gauges are calibrated in easy-to-read 1 lb. graduations. Made in USA.