Slam Balls range in Weights are from 2 lbs. to 50 lbs.; made from Tough Rubber to Handle High-Velocity Impacts against Hard Surfaces. Slam Balls are a favorite in CrossFit Training and allow a Full-body, Compound, Multi-joint Exercise that Generates Explosive Power and Core Body Strength. Slam Balls are perfect for HIIT Training or just capping off a Workout with some Cardio.