This SKLZ training ball is weighted to instantly show if contact is solid. If the hit is square, the contact ball will fly straight, if the strike is off center the ball will fly wobbly and shorty. Player errors are clear to see by how the ball reacts. The added weight trains players to use their core and swing through the ball. This training ball conditions players to have more consistent contact, better follow through, and a stronger overall swing. Buy several contact balls for rapid fire drills that teach players to get back to their starting position and promote proper mechanics. Use this ball to train baseball and softball players.