Ebike Pas D17 Magnetic Disc for Pedal Sensor 12 Magnets Waterproof Plug

UK EAPC compliant – for pedal bicycles only, not e-scooters or mopeds. Installation: It is screwed to the chainring (4x). An adapter for a 5-arm pedal crank is included. Disassembly of the bottom bracket is not required.

eBay