Iris Usa- Inc. DIRFT940 Premium Dog Training Pad Tray - Nextag Stores
I have tried all of the "potty pad holders" but like the one that has a hinge in the middle - lasts longer, but is also a bit more expensive. Comes in several sizes. I buy my potty pads at Sams - they are for human people, but good sized and somewhat less expensive - buy them in a big box. They fit the large holder quite nicely - get them in the health department somewhere near the pharmacy.
Hope this helps.