Special lock washer used to lock the top prop nut in place. Place the washer over the eye at the end of the top bow, place the top bow on the stud and screw on prop nut. The tabs on the sides of the washer are then bent up against the square nut area on the back of the prop nut, preventing the nut from twisting off.
This is an aftermarket accessory
For use with
33708L,
33708BL and
33708BQ.