Some come with a door (gate) to open and some do not. The first one we bought was 36" and no door. I could not reach over to pick Mia up. We took it back and traded for a 30" and a door. I am so thank full we got the door. When she isn't in there I leave the door open with a puppy pad inside and she goes in for her potty time. Took to it right away. I would go for the middle height, 30". Depending on how big the puppy gets there is a chance with the 24" that he or she will master jumping out. Believe me I have two yorkies and they love to jump and can do it well.
Telea Zoe' and Mia
