Design & Details: Set of 6 balls 3.5 oz-green, 5.5 oz-yellow, 8 oz-red, 11 oz-blue, 16 oz-black, and 32 oz-gray weighted balls 6 Pack ball diameter is 2.9" for all balls except the large gray ball and that is 3.2" Set is excellent for pitching training, for pre-game warm-up, and for all baseball or softball players Weighted baseball training balls are filled with iron powder which will do less damage to the inner lining of the ball unlike sand and other materials (not rough) Provides extra longevity to the ball Less filled balls will allow you to get a better grip when practicing These pitching weighted balls will help to improve functional strength like rotational power and speed that is essential to arm health and increased velocity Also, can be used for rhythmic stabilization for the shoulder Assist your rehabilitaion efforts to building that muscle back up to perform at a peak level Come with a convenient carrying bag that is made of nylon and mesh with a drawstring close Works well for the softball, football, lacrosse, pickle ball, tennis, racket ball, basketball, and golf athlete as well Each plyo ball can withstand multiple throws and hits to any smooth surface whether it is indoor or outdoor including wood, pads, or nets due to its pvc shell and design Do not throw against cinder blocks or any rough surface If after extended use the ball starts losing shape, simply use an inflation needle to give the ball a pump of air Specs: Material: Nylon, Rubber Outer material: Rubber Item weight: 4.9 Pounds Package weight: 2.28 KG Item dimensions: 10" x 6.6" x 6.6" Item package dimensions: 13.5" x 9.45" x 3.23" Included components: 6 Weighted plyo balls