Our new 1/16th scale mini E-Revo and mini Slash Axle Carriers have a unique pivot ball retention system that locks the pivot ball in place, yet still allows for adjustment due to wear. Our system is based on a cap design, held in place with a pair of small screws. Simply slip the caps in place, tighten the flathead screws until the free play of the pivot ball is eliminated and you're ready to go!