Support OBDⅡ Air-fuel ratio gauge can accurately detect whether the oxygen concentration and engine works well. It is a highly precise test instrument which measures the oxygen concentration in the exhaust gas to obtain the burning AFR signal of internal combustion engine. Product Features: High Sensitivity Sensitive reading, capture subtle changes Touch to change color, touch-sensitive, light color switching easily Read Clearly The pointer has blue and red colors. The value change can be clearly observed in daytime and night. Several Gauges Connected in Series Several gauges connected in series can display different data simultaneously, fully control your car. it is recommended to connect no more than 5 in series. One key to zero Is the gauge placed unevenly? One key to zero, the value can be displayed accurately at any odd angle Aluminum Ring Color 7 kinds of aluminum ring color, choose by personal preference. Gauge Cover(purchase separately) Gauge cover of different colors, gorgeous appearance, strong shading effect, even in the dazzling sunshine, it can read clearly. Buy more than 3 gauges at a time will enjoy a discount, please click the top right corner to send inquiry for getting the discount coupon. If you are a wholesaler, please send inquiry to us for the wholesale prices!