Lot of you people asked me what this box is for? This is called as or a or a for a pregnant dog and her puppies. It is designed to protect puppies during birth (whelping) and early life by keeping them safely contained, protected from cold, and safe from the danger of crushing or smothering by the mother. It also helps to keep the young puppies in a restricted area, close to the mother and other siblings. The door is to give an easy but controlled access to The female to move in and out. We don't encourage the female to jump in or out. The black arrow showing is called a puppy rail guard, it helps to keep puppies safe from being crushed or smothered by the mother dog while she is inside the box with puppies. Sometimes accidently, unknowingly the mother dog sits on the young pups. This is majorly considered with a large breeds. Inside the box there will be thick layer of cloths, papers which will keep the puppies warm!