I really like the original model, but I wanted it to be as small as possible. It's thin enough to push the A1 about as close to a wall as it will get, and includes a lip to prevent some stray poops from getting under the bed. Compatible with AMS Lite top mount. I didn't use supports but the bottom of the lip looks awful because of that, but no one will see it so I don't mind, I recommend tree supports with threshold at 35 degrees