Living World Medium Tunnels are designed to attach to the Living World Small Tent for small pets. It provides extended space for play and exploration. These flexible tunnels can also be used as stand-alone toys for tunneling and burrowing. Constructed of polyester fabric that makes crinkling noise for added amusement. For indoor or outdoor use. Large tunnel is suitable for ferrets; rats; guinea pigs and dwarf rabbits; 5.9 inch diameter.