... .Display Function: LED Meter Display function. Mileage, speed, timer, options of speed,vibration alert, the battery level, Over ... modeInertial navigation moduleDisplay functionsLED Meter Display function. Mileage, speed, timer, options of speed,vibration alert, the battery level, Over ... quality problem, we will ship free charge spare parts during 7 days by air.Terms of PaymentT/T ( bank to bank ) ...