The Medium Gear Bone features double spinning gears in the center and teeth cleaning spiked gears on each side. Each gear rotates freely on a rubber spindle to keep things lively and the multi-colored gears are easy to spot in any situation. Great all-around play toy for just about any dog. LARGE GEAR BONE At 70% more weight than the Medium Gear Bone, the Large Gear Bone is designed for our tougher big dog customers. With rotating double gear sets on each side and three rotating teeth cleaning rubber gears in the middle, this toy is ready for the toughest customers the dog world has to offer. All the while cleaning teeth and gums. SMALL GEAR BONE At 6.4 ounces, the Small Gear Bone is designed for our smaller dog customers. Featuring three rotating gears with either spikes or nubs, this toy will clean those little teeth with ease and provide hours of play for even the most finicky dogs. Just as tough as our bigger Gear Bones, the Small Gear Bone will provide long-term fun.