Aspen Pet® Self-Warming Bolster Kennel Mats are constructed using space blanket technology. A Mylar interior layer creates a safe, convenient way for cats or dogs to stay warmer by reflecting a pet's body heat and retaining that radiated body heat. No electricity is required. Made with contrasting corduroy and supple comfy faux lambswool with plush sides for pets that like to burrow. Also will fit into a 24" plastic or wire kennel to provide extra comfort. Anti-skid fabric on the bottom. Lightweight for easy transport makes it perfect for vacations and road trips. Machine washable.