Although I would not really consider this a playpen, it does serve the needs - one cat has to be retrained to litter after suffering abdominal issue for a year and fearing the litter box.  The other needs meds and does not get along with the others - room being prepped for him and his sister.  One was easy to set up, the other did not fit well where they should slide together, but made it work.  Gives the cats more room than the large dog crates I borrowed.