ATEC HI Per Pro Baseballs and Softballs (Pack of 12) Specifically designed to be used with baseball training machines Premium full-grain leather minimizes residue buildup and maximizes ball lifespan. Safe for use with Performance Bats Low-profile high-tensile-strength Kevlar Accu-Seams maximize ball flight accuracy and durability Regulation Baseball Size & Weight. Regulation Red Cushion Cork Center Indoor & Outdoor Training Approved. Pack Size: 12 balls