Looks like those Mytee handles. Cobb has them.
Best $21 investment in the industry !
http://www.cobbcarpet.com/zen/index.php?main_page=product_info&cPath=68&products_id=4995
The zipper on the portable was pretty impressive with the recovery of water... Chavez was a seasoned pro when it came to portables! Dude could boogie with that potty setup...