These Action and Viper Weight Bolts will fit inside the stackable weight bolt system of Action, Mayhem, Stealth and Viper Cues. Customize the feel of your cue by adding or subtracting weight bolts from the butt. Available weights are 0.5oz or 1.0oz. Easy to install just pop off the butt cap from the butt end of your cue and with the use of a 8mm Hex Key or Allen Ranch Tool (not included) unscrew the old bolt out and then screw the new one in. Adjusting the weight on your cue could be the factor of winning or loosing a game.