We recently adopted a puppy Chihuahua and use this to confine him when necessary and also as his bed.  We ordered the 36 inch and it's actually smaller than we figured.  Once you put bedding in there, there isn't much room for him to go potty in the middle of the night (he's only 10 weeks old)  So we took a metal crate that we had and we lined with puppy pads. We butt the crate door up to the pen to form a little condo for Tuffy.  At night, when he wakes up, he leaves the pen (his bedroom), goes into the metal crate (his bathroom), goes potty, then goes back to his bed in pen.  This is a high quality crate and we expect to have it for many, many years.  The zippers are both very high-end and we like that the bottom is sewn to the sides of the pen rather than velcro or a zipper.  Less chance for escape. as well as any accident leaking through to the carpet.  You won't be disappointed!