Shimano SM-EWSS2 Speed Sensor Magnet Adapter Keep Your STEPS System Reading Right When the speed sensor on your Shimano STEPS e-bike loses its magnet signal, the assist system can't do its job. The SM-EWSS2 magnet adapter is the fix. It mounts with your Center Lock rotor at the rear wheel and gives the chainstay-mounted speed sensor a clean, consistent trigger point on every rotation. If yours is worn, missing, or damaged, this is the part that gets your system reading accurately again. Features Center Lock rotor mount installs with the rotor at the rear wheel hub for a clean, integrated fit Shimano STEPS compatibility works with the STEPS speed sensor system to deliver accurate wheel speed data to the drive unit Supplied special lock ring required must use the included lock ring for proper thread engagement and secure installation Direct OEM replacement restores accurate speed detection when the original adapter is worn or missing Compatible disc rotors : RT-CL900, RT-CL800, RT-CL700, SM-RT64, RT-CL300 | Shimano | Sm-Ewss2 Speed Sensor Magnet Adapter Sensor