Thermo-Crinkle Sack is the perfect play and sleep spot for any age cat. With built-in noisy walls, all cats find it as irresistible as that paper grocery bag left on the floor. With its plush interior and soft heated floor, its bound to be kitty's favorite sleeping den as well. Pop the energy efficient 4 watt heater out for year round fun and comfort. Machine washable. Indoor use only. Limited one year warranty.