Abstract: A cover replicating the appearance, texture, and surface features of a regulation baseball enclosing a flexible, hollow, spherical core. The core is fabricated from a pair of substantially similar semispherical shells made of a homogeneous, waterproof composition and bonded one to another at the circumferential edges. The composition from which the core is formed includes by weight 30-40 percent styrene butadiene rubber, 16-20 percent natural rubber, 33-37 percent calcium carbonate, and 5-9 percent silica powder, as well as diphenyl guaniden, rubber cure accelerator, and traces of zinc oxide and sulfur. The outer diameter of the core is approximately 2.6-3.0 inches with a wall thicknesses in the range of approximately 0.08-0.16 inches. The core with the cover assembled thereon has a weight of approximately 2.5-3.5 ounces, less than that of a regulation baseball, and an outer diameter substantially equivalent thereto.