Trumark's 5/16" steel-ball slingshot ammo has been carefully selected for its SPECIAL SIZE; it's not too small and it's not too large. Ammo that is 1/4" in size is too light and tends to "tear up" wrist-braced slingshot bands that need more weight in the pouch when shot. Steel ammo that is larger than 5/16" or 3/8" is too heavy and is unsafe if used improperly. 5/16" ammo is a good balance between light and heavy, and it is the ideal sized steel-ammo to use in WRIST-BRACED SLINGSHOTS. 72 Count.