bicycle speedometer: qualitied assitant--biclble 0dometer(yt-812) - speed range:0-199.9m/km/h - real-time display of the current speed, trip distance, riding time, and rotations per minute (rpm) of the wheel - easy viewing of maximum speed, average speed, calorie consumption, and total distance - with clock - solar-powered design (upon request) - configuration of the riding time, trip distance, calorie consumption, and automatic alert - real-time indication of the acceleration of deceleration for easy control of your speed - night light for safe cycling - length unit options of kilometer/mile - multiple purposes for bicycles/motor bicycles (7.5 to 30in) - modern look, waterproof, and portable - product dimensions: 7.5 x 5 x 2cm - carton dimensions: 40.5 x 27.5 x 30.5cm (60pcs/carton) - net weight: 5kg - gross weight: 8kg.