*This is for the washers only. The pulley wheel and bolt is sold seperately.
2 small washer replacements for glowforge pulley wheels. Each pully wheel (The wheels your belts wrap around) has a small washer behind it to prevent the wheel from rubbing against the gantry/frame and creating friction that would inhibit the movement of your machine.
If you are replacing your pulley wheels you need to remove the bolt and washer, which because of its size is prone to being lost. Having a couple on hand is good in case they get lost as installing a pulley wheel without them can damage the machine and cause your machine to produce warped/off engravings/cuts.