The Hyskore DLX Precision Shooting Rest Spring Kit contains six different springs. Each spring has varying levels of resistance. Change out the springs accordingly to achieve the desired level of recoil. Springs are compatible with the DLX Precision Shooting Rest. FeaturesFor use with firearms with 18 ft/lbs recoil or lessPack of 6Easy to installIncludes Yellow - 2 lbs/Inch of Travel (2)Blue - 4 lbs/Inch of Travel (2)Green - 6 lbs/Inch of Travel (2)