Competition Engineering 3-Way Adjustable Drag Shocks are designed to allow the racer to dial-in the race car to meet changing track conditions. Shock valving plays a very important role in the way your car will perform both during initial launch and throughout the quarter mile. The principle behind this shock absorber design is to allow the front end of the race car to rise rapidly upon initial launch, creating greater weight transfer and better traction to the rear tires. As the car travels down the track, the front end will gradually descend to its ride height without unloading the rear tires which is a major cause of wheel spin. Competition Engineering rear shocks work in conjunction with Competition Engineering front shocks making the transition from initial launch to top end charge as smooth as possible. Competition Engineering Rear Drag Shocks can be adjusted for changing track conditions by simple compressing and turning the shock. For slick tracks, set to the 50/50 adjustment; on good tracks, set to the 30/70 for better weight transfer. Rear Drag Shocks are also adjustable in three ratios: 30/70, 40/60 and 50/50. These ratios also represent the percentage of force required to compress and extend the shock unit. Only this time, the first number is compression and the second extension. These shocks also adjust by compressing them fully and rotating to the desired setting on the body. Shocks are sold individually.