Fido can't decide on today's game of choice? No problem. With the Chuckit! Fetch Ball Medley 3-Pack, he can chase a different ball each time. The medley packs vary by size but both include the Fetch Whistler and Fetch Max Glow Ball. The Rebounce ball comes in the medium size pack and the Erratic ball comes in the small pack. No matter what size each ball is unique and will give you and your pup endless options of fun! is designed to fit the Chuckit! Medium Cup Launcher. Stretch those legs, Tucker! You're going to need it!