The SKLZ(R) Contact Baseball promote consistent contact and stronger swings while being built with durable materials so they can out last the strongest hitters. Advanced Training Instantly shows when hitters make solid contact Develops proper follow through and a stronger swing Easy to implement in any baseball training routine Built to last with solid, durable materials Specs: Balls included in purchase: One Weight: 15 oz Model: BBCB-001 1 year limited warranty SKLZ