Aspen PetÂ¨ Self-warming Bolster Mats are constructed using space blanket technology to create a safe, convenient way for pets to stay comfortable in cooler climates by reflecting and retaining your pet's radiated body heat. No electricity is required. Made with contrasting corduroy and supple faux lambswool plush. Designed for plastic and wire kennels to provide extra comfort. Anti-skid fabric on the bottom. Lightweight for easy transport. Machine washable.