Using our special multi-layer self-warming material, the K&H Self-Warming Lounge Sleeper will keep any indoor pet warm and cozy. Metalized insulation inside the bed's pillow reflects a dog's or cat's own body heat. Any pet will love this bed for its comfort as well. The outside is made of a poly/cotton blend while the sleeping area is covered in a soft microfleece. The bed's pillow contains a soft, extremely comfortable polyfil made from recycled bottles. Its sidewalls provide a cushioned feel that's perfect for dogs or cats that like to snuggle. The Self-Warming Lounge Sleeper comes in several size and color options. Larger sizes with the checkered pattern also include a removable liner that makes washing easy.