Spacious Pen: This dog whelping box measures 41" x 39.25" and is suitable for small to large breeds. It includes a pig rail to protect newborns from potential squeezing hazards from the mother. Easy Access and Security: With a height-adjustable door, the mother dog can come and go safely while ensuring the puppies' security. This whelping box is sealed to provide the pups with a wind-resistant living area. Sanitary: The whelping pad lining the base catches messes for easy replacement, keeping the space fresh when used. Improved Conditions: A retractable light stand positions heat lamps at an optimal angle for regulated temperature control as puppies develop. Puppy Playpen for Dogs Info: Overall Dimensions: 41" L x 39.25" W x 19.75" H. Single Panel: 39.25" W x 19.75" H. Assembly required.