Living World Colorful Cardboard Chew-Nels are durable, interconnecting cardboard tunnels that provide small pets with hours of hiding, chewing, and rolling fun. One of the unique things about Cardboard Chew-Nels is that they can be connected to other Cardboard Chew-Nels to create longer tunnels. In addition, they are stuffed with soft, fluffy nesting material that will delight small pets while satisfying their natural burrowing instinct. Cardboard Chew-Nels are made of cardboard and parchment that is finished in vibrant colors, made from non-toxic, food-grade colorants. For added fun, cut a hole in a cardboard box and insert a Chew-nel or two!