Upgrade the performance and handling of your HPI Formula Ten car with this threaded aluminum rear shock. The lightweight aluminum shock body is threaded for precise spring adjustments that allow you to quickly tune the handling of your car to track conditions. Silicone oil (#300) is included, along with a track-tuned spring, machined 3-hole shock piston and a knurled adjustment ring. The set includes everything needed to replace the stock plastic shock with a high performance alloy racing shock for faster lap times!