Product Description Material: ABS Size: 4.6 * 4.6 * 1.8 cm Colour: Black Display: LCD display Backlight: Green/White Features: wireless automatic wake-up Power supply: 1 CR2032 button battery on the meter head; 1 12V 23A battery for the transmitter Quantity: 1 pcs Package content: 1 pcs * bicycle odometer 1.Auto Wake-up FunctionAutomatically wakes from sleep mode upon sensing vibration in the bicycle. Bright LCD display to easily view ride statistics. 2.Multi-functionsSmall size, light weight, wireless, waterproof design makes it convenient and durable. This bicycle computer measures speed, distance, and riding time. Exactly what any serious bicyclist or fitness fanatic needs to know for stats tracking. 3.Day & Night Backlight Provides backlight for easy viewing during dark hours. The backlight will automatically turn on when any button is pressed between 18:00 and 06:00. Please note the slight rattle sound from device is normal phenomenon, which results from the design of wireless automatic function. 4.Easy to Install &UseSimple installation that only takes a few minutes. Easy to navigate interface with only two buttons to access all measurements. Customizable to most common tyre sizes for accurate stats tracking. 5.ApplicableRoad bicycles, mountain bikes, folding bikes,and other common bicycles are compatible with this bicycle computer. This bicycle computer MAY NOT be compatible with some electric-assist bicycles. If the computer display, sensor, and magnet can be installed within the specified distances device should be fully compatible. Please do not hesitate to contact us with any questions.