Each ball in this collection features 1 of the 50 greatest bowlers in PBA history on one side with the PBA 50th Anniversary logo on the other. The balls are limited edition - only 50 of each will ever be made. Each individually numbered ball comes with a Certificate of Authenticity signed by the bowler or a representative of his estate. This is one of the many "stock licensed image" bowling balls that are available. Custom "stock image" bowling balls take 2-4 weeks for production and shipping. These are made of a polyester material. The image is actually embedded in the surface of the bowling ball and does not wear off over time. These bowling balls are perfect for the recreational bowler, bowler's who prefer to throw the ball straight and competitive bowlers for shooting spares at those pesky corner pins.