These magnetic rings clamp to the axle on a kart to provide a signal for the Alfano speed sensor. The rings contain a single magnet to trigger the sensor and are available in various diameters to suit all common kart axle sizes. A 4 magnet version is available for 50mm axles and provides a faster responding speed signal.

Clamps to kart axle
For use with Alfano speed sensor

 

25mm