Mean Mother Tyre Pressure Gauge 3 1/2inch Mean Mother tyre gauges are shock resistant, reliable, easy to read and operate. They have ANSI (American National Standards Institute) grade B accuracy. All our gauges have been tested to ANSI standards for their precision and accuracy. The classifications relate to the scale of the gauge. The scale of the gauge, commonly referred to as the pressure range is divided into three equal portions when characterising its accuracy. For example 0-20psi, 20-40psi and 40-60psi portions of the dial. Mean Mother gauges have a Grade B accuracy, meaning the accuracy for the 0-20psi and 40-60psi portions fall to within 3% of the actual pressure being measured. The middle portion is the most accurate and in this case would be accurate to within 2% of the pressure being measured. When selecting a gauge for your application you should select one where the middle portion will be the pressure range required. For this reason all Mean Mother gauges are 0-60psi which is most suited to the 4WD and standard vehicle market. Mean Mother tyre gauges achieve this accuracy and reliability because of the quality of components and design. They feature a unique diaphragm made from a composite material that is sensitive to even the slightest change in pressure and will never lose their shape. Most common tyre gauges are constructed using a bourdon tube with mechanical gears. Its generally acknowledged that when the bourdon tube receives a sudden boost of pressure the internal gearing activates to move the pointer. The gears can easily fail as a result of the torque generated from this action. 3 1/2” Dial, 0 - 60 psi, 45cm rubber (NBR) extension hose. Rubber body impact protection cover. ANSI grade B accuracy. 360° swivelling brass valve connector with deflation nipple and air release button. Stored in a blow mould case.