I got Lexi's new exercise pen over the weekend. I got the 24" high pen from PetSmart. I ended up getting some indoor/outdoor carpet to use under it. The great thing about the carpet is that it is light weight and easy to move and store. The carpet was $26 but it comes in 12 foot wide sections. I got a 5'X12' piece and then cut it in half. That left me with 2 5'X6' sections. My parents took the 2nd piece home so that I don't have to bring mine with me when I come.