I think it stands for exercise pen...and can be used for just that. An area that can be fenced off for them to play without getting into anything. I loved it when Winston was a little puppy. I used it to keep him out of areas of the house until he was completely potty trained. I couldn't use it to prevent him from going to the bathroom in the house, where if he was in his crate he new to hold it.
My advice - still use the crate because that helps with the potty training and use the ex pen to keep them out of things or confined to a certain area.
Also, when Winston was a little guy I could put him in the ex pen with a potty pad and get things done around the house. Now that he is almost one we don't really use it anymore because he can roam the whole house.
Hope this helps - good luck!
