SPD/CAD SENSOR , exquisite and compact, accurately 
capture bicycle speed data, easy to install,no magnet, wireless 
data transmission via Bluetooth or ANT+ protocol, 260 hours long 
battery life, has passed IPX7 waterproof test.


In cycling, cadence (or pedalling rate) is the number of revolutions of the crank per minute; this is the rate at which a cyclist is pedalling/turning the pedals. Cadence is directly proportional to wheel speed, but is a distinct measurement and changes with gearing—which determines the ratio of crank rpm to wheel rpm.

The speed sensor is used to detect the speed of the bicycle. The small data is transmitted wirelessly to the computer or other devices one by one.