NOTE There is a protective film on the surface of the bike computer, please reomve it before use. BIKE COMPUTER SETTING Step 1: Set the wheel perimeter Press the SET Button and the MODE Button together for seconds, the original number will blink on the display. You could press the SET Button to change the wheel size, the unit is MM. Step 2: Set the speed unit After step 1, Press the MODE to the words kmh, press the SET Button to change it to mph or not. Step 3: Set the weight After step 2, press the MODE Button to the weight setting, press the SET Button to change the weight of rider, the unit is KG. Step 4: Set the clock After step 3, press the MODE Button to the clock setting, press the SET Button to change the time. SPECIFICATION Headlight: Headlight brightness: 800 lumens Lighting mode: High lightLow lightSingle lightStrobe Effective range: 275m Electronic horn: 120 db Working time: 612hrs Computer life: over 3000hrs Rechargeable Battery: 4000mAh Charging mode: USB charging Charging time: 34hrs Sensor battery: CR2032 Sensor battery life: 12months, 1hrday Waterproof: IPX6 Weight: about 170g(0.37LB) Size: about 16013550mm Tail light: Brightness: 50 lumens Effective range: 50m Lighting mode: High lightQuick FlashSlow FlashStrobe Rechargeable Battery: 330mAh Working time: 410hrs Waterproof: IPX4 Weight:22g(0.05LB) PACKAGE 1 3 in 1 Bike Computer 1 Bike Rear Light with Bracket 1 Lighting and Sound Controller 1 Controller Fixed Strap 1 Bracket 1 Magnet 1 Sensor 2 CR2032 Battery 3 Cable Tie 1 Installation Kit 2 USB Charging Cable 1 Manual