Sliding dampers use different viscosity greases to control the dampening effect when a Mini 4WD car takes a corner at high speed. By using different viscosities, you can change the handling characteristic of the car as it bounces off the track corners. Includes 2 types of grease: Extra Hard (red) and Extra Soft (blue). Applying the grease to your sliding damper reduces the spring effect after the machine hits the wall, gaining your machine time over the opposition! The two types of grease can be mixed to make a custom viscosity tailored to your machine.