You can find all the replacement parts you need at Escapa.
The Shimano EW-SS301 Speed Sensor is the perfect replacement for your eBike with a Shimano Steps drivetrain. The flat sensor is particularly well-suited for use on E-MTBs and is mounted on the left dropout near the brake disc.
Exclusive MTB design
Designed to work with all disc brakes available for the Shimano Steps E-BIKE system
Compact and clean design
For brake disc magnet
Updated with new SD300 electrical cable
Cable length (mm): 760, 1400
Does not include magnet set