Turns Suunto training instrument into a wireless bike computer. Current and average speed plus distance alarm are displayed on the Suunto T3, T4 and/or T6. Sensor attached to the hub with a regular sized locking lever / skewer. Range up to 10m/ 30 ft. User replaceable battery CR2032. Comes with spoke magnet for regular and flat spokes, and bike adapter. Not usable with extra thick 20 mm downhill axis!