SKLZ Bolt Balls Bucket of 50 Soft Micro Training Balls for the Original Lightning Bolt Pitching Machine. Ideal for players of all ages and skill levels the small 4” circumference size encourages players to focus more on the ball which helps them remain focused throughout their training session. Soft practice balls can be used for safer practice or where less ball flight is necessary such as at the park or in the backyard. Same practice value and no broken windows. Bolt Balls come in a bucket of 50 and are a great practice tool for both Baseball and Softball players.