The use of UnderLoad and OverLoad baseballs has been debated for years in the baseball and medical community, but the most up-to-date scientific research points to weighted baseballs being very beneficial in developing arm health and velocity.
Each set of weighted baseballs consists of 6 Baseballs:
UnderLoad Baseballs (less than a 5oz regulation baseball):
OverLoad Baseballs (more than a 5oz regulation baseball):