Operating instructions: Turn on the device and wait for the full display to appear. The first line shows real-time time, calories, distance, and time metrics. Press the Mode button (left button) to switch functions on the first line. In the current function interface, press and hold the Mode key to enter the setting or clearing state. For example, in _DIST mode, press and hold the Mode key to enter the setting state. In the setting state, continue pressing the Mode key to cycle through digits and use the Set key to adjust values. Only time, distance, and real-time time can be set; all other data will be cleared.The second line displays distance. Press the Mode and Set keys simultaneously to access settings for kilometer/mile units, wheel circumference, and weight. The default wheel circumference is 2060mm, adjusted using the Mode and Set keys. After setting wheel circumference, 070 will appear, indicating a default weight of 70kg.The third line displays current speed, maximum speed, average speed, temperature, and distance in kilometers or miles. Press the Set key to switch between functions; short press to change modes, long press to clear data.Backlight defaults to automatic mode. The backlight activates for 5 seconds when the time is between 18:00 and 06:00. Press and hold the LED key for approximately 3 seconds to enable constant backlight; press and hold again for 3 seconds to disable it.Equipped with horn and headlight dual-line control, allowing operation without removing hands from the handlebars. High-decibel electronic horn produces a 120dB sound to effectively alert pedestrians.Features a high-definition LCD screen for clear reading. Multiple modes are available, including mileage, riding time, clock, stopwatch, and calorie tracking, with easy switching between functions.Intelligent sensor automatically wakes the device upon vibration detection and enters sleep mode after 3 minutes of inactivity, enhancing durability.Designed with life-class waterproof performance, resistant to splashing water and suitable for use in rainy conditions. Avoid prolonged exposure to heavy rain.Product Name: Bicycle Headlight Wireless Meter Material: ABS + Electronic Components Weight: Approximately 311 grams Color: Black + Blue Type: Bicycle Accessory Power Supply: 3.7V Lithium Battery Buttons: MODE, SET, LED External Controls: LED Key, Buzzer Key Package Contents: 1 x Meter Lamp Body 1 x USB Cable 1 x Installation Kit Note: Light reflection and differences in display screens may cause slight color variations between the image and the actual item. Measurement tolerance is +/- 1-3cm.