Traxxas TRX-4 owners, this is an awesome upgrade for your locking differentials! This GPM set gives you three lightweight, super strong aluminum servo horns made from 6061-T6 aluminum. The coolest part? They have a built-in spring that acts like a shock absorber, which helps protect your expensive servo from getting damaged by hard impacts and jolts when you're crawling over rough terrain. It's a direct replacement for the stock plastic part #5669. The kit comes with everything you need: the three orange servo horns, three stainless steel screws (3x10mm), three aluminum collars, and three 3mm metal washers (remember to put the washer under the screw head to avoid any gap). It's a simple swap that adds durability and a bit of flashy color to your TRX-4 Defender (model 82056-4). Definitely a smart upgrade for serious crawlers.