The Accu-Gage Professional Tire Pressure Gauge has a fully geared, precision movement with bronze Bourdon tube. Unlike piston-plunger type gauges, the Bourdon tube movement is not affected by changes in temperature, humidity, or altitude. Flexible 11 inch hose between gauge and chuck for hard-to-reach tire valves. Needle holds pressure reading until released. Push-button valve bleeds air to desire pressure. Protective rubber guard installed. Lifetime Warranty (USA and Canada).