This is a brand new rear sprocket bolt lock plate tab washer
This is what keeps your sprocket nuts from backing off the hub.
Each unit requires 3 of them
fits:
Yamaha Banshee 350 1987-2006
Yamaha Blaster 200 1988-2006
Yamaha Warrior 350 1987-2006
Replaces Yamaha factory OEM # 2XJ-25412-00-00