The Franklin Sports Lacrosse Balls 12-Pack are official size and weight that are perfect for play in the backyard, at recess or any sort of training or recreational play. They are the standard 63 millimeters in size and 5.25+-.25 ounces in weight. They are multi-purpose lacrosse balls that are ideal for training and recreational play but also double as muscle relief aids. They can help increase mobility and aid in recovery. They are ideal for yoga, body maintenance & flexibility. They can be easily used for massage therapy by simply leaning on the ball with your body weight to allow gravity to relieve muscle knots and tension. Optimal for using anywhere that is convenient for you whether that be at home, the office or the gym. Constructed of 100% vulcanized rubber this set is perfect for training by players of all skill levels. Play with confidence knowing these were designed with performance and quality in mind. All balls are official size and weight and ready to train, play and score.