Tennis Ball: High visibility two-tone ball, extra wall thickness Erratic Ball: Stimulating random bounce, easy to clean, natural rubber Whistler Ball: Twitters and whistles in flight, easy to clean, natural rubber Max Glow Ball: Bright, long lasting glow, charges quickly under any bright light, easy to clean, no batteries needed Floats, high bounce, easy to clean, natural rubber Fits: Junior, Classic, and Ultra Launchers