To me, a good whelping box will hold a nest full of puppy's. will be able to have a heating pad in it, blankets, able to create a bumpy floor, not near drafts. made of wood or plastic. most are home made and lots of people use kiddie pools. I use a large tub and took the puppy's out to the mom. I don't have any suggestions on anything in specific, as long as it works and easy enough for you and mum. Sorry if I am of little help. I have seen home made ones out of wood 2 x 4's but where do I put it when I'm done? I don't put much stock into the box as much as I do taking care of those little ball's of fur. What ever you decide you will have to get them to mum every two hours and it's dedication no matter what