These allow you to change your tire without the chain adjusters falling out and they accept spools so you can do your maintenance with ease. It makes removing and installing your wheel so much easier since they get held in place inside the swingarm even after you remove the axle.
We recommend Delrin spools compared to aluminum because of their shock-absorbing characteristics when crashing. You will be more likely to bend or break the spool rather than strip out the threads of the chain adjuster itself.
