The Brass Rear Axle Cap Weights are designed to enhance the performance of your RC vehicle by adding non-rotating mass to the rear axle housing. This adjustment helps in fine-tuning weight distribution and lowering the center of gravity, which can greatly improve handling and stability during operation. These weights are a direct replacement for the caps on the ends of several axle models, including the VS4-10 D44 Rear Axle, SCX10-II F9 Rear Axle (non-portal), SCX10-II Rock Jock Rear Axle, and the VS4-10 F9 Rear Axle (non-portal).