Structural foam construction which is 3 layers thick providing extra strength and durability. Nitrogen insulation keeps it warmer in winter and cooler in summer. Adjustable ventilation regulates air flow and reduces condensation. Extended door entry and raised door threshold allow pets to get away from the elements. Easy snap lock allows for convenient assembly and cleaning. Overall size: 39.3" W x 30" H x 51.5" L. Door size: 17.6" W x 17.3" H. Extended door entry: 22". For optional door refer to Model No. 29998 (SKU 806579).