Power Force Weighted Softballs | 3.25" Diameter - 15 oz | Weighted Training Softballs for Batting Practice COLOR CORRECT Sports Researchers have determined that color is the most important element in repetitive memory development. Power Force Softballs are optic yellow, which increases the players memory response during actual game conditions. STRONGER HITTERS Teaches Hitters to drive the bat barrel through the ball and finish their swing strong. Strengthen fast twitch muscle fibers for more power. INSTANT FEEDBACK Players, Coaches and Parents instantly know if there's good contact. PRACTICE HITTING ANYWHERE Outdoor Practice, Indoor Practice or Tight Tournament warm-up area. Limited flight and won't damage surfaces. MORE DURABLE Thicker Shell and Temp-Just Valve System give Power Force Softballs the highest durability and performance of any Heavy Ball sold.