BUILT FOR MODERATE CHEWERSOur best-selling customizable puzzle and treat toy is designed to be filled with a dog's favorite kibble or treats. Toppl's soft, rounded inner 'teeth' contain a contoured cavity to hold treats in place until your dog nudges them out. To change up the challenge, simply connect the XL and Large or Small and Large together.Pair with Toppl Stopper to block Toppl's side hole to keep liquids safely inside.