The outside of the bed is in poly/cotton and the inside is lined in soft microfleece. The pillow has a layer of metalized insulation that radiates warmth generated from the pets own body heat. Completely machine washable and filled with premium polyfil made from recycled plastic bottles. The bottom of the bed has a layer of "stay put" non-slip fabric for stability. Self-warming material radiates heat back to your pet Non-slip bottom for stability Warmth with no electricity needed Fill made from recycled plastic bottles Sleeping Dimensions: Medium: 26" x 35"