1. Digital Display: Display speed, water temperature, instantaneous fuel consumption, hour fuel consumption 2. Performance Testing: Vehicle acceleration test 3. OBD2 Engine Diagnostic Functions: Data flow function display, display color configuration, fault code scanning, fault code clearance and other functions 4. Early warning function: Water temperature warning, over speed warning, shift warning. Specifications: Operating voltage: 9-18V DC Operating current: less than 80mA Sleep current: less than 10mA Operating temperature: -20~85℃ Product volume: 75mm x 55mm x 20mm Speed meter indication error Speed Meter indicates speed and actual speed according to formula : O less than or equal to Vn- less than or equal to (V: + 10) + 4 V1- speed meter indicates speed in km/h V2- an actual speed in kilometers per hour (km/h). The vehicle speed correction is based on 100km/h. The error of the vehicle in the low speed state is the reason why the original vehicle meter is not linearly displayed.