Locking washer for inner nut on clutch.
21 mm inner diameter
32 mm outer diameter not counting the tongue that sticks out a bit.
Sachs original number 1024405-2005
Number 31 in exploded view of the clutch etc.
Also works as a replacement for Sachs original number 1024405-2000 that is used on the pedal axle.
Number 16 in the pedal axle exploded view.