Standard billiard balls are crafted from the highest quality phenolic resin, providing exceptional scratch and impact resistance. Phenolic resin is proven to last up-to 5 times longer than balls made of polymers or polyester. Each ball is regulations size, measuring 2-1/4" in diameter. This complete set of 16 balls includes 8 solids, 7 stripes and a cue ball. Aramith billiard balls adhere to the most stringent specifications in the industry, ensuring superior playability and durability. They are constructed with perfect roundness and balance, uniform weight and hardness, brilliant colors and a friction resistant roll.