Ok, here are some pictures of the drawer with rollers on the top, rear both sides...
Then small rollers, two pairs. Each pair are on each side of the floor about 8 inches apart. The floor portion they are mounted into is like the rest of the box, 1" marine grade plywood. The floor extending beyond this all the way to the rear is 1/4 press board. This particular box had a damaged floor (the press board part was blown out under one of the drawers...there was a fire extinguisher discharge on the top - lots of hard white chemical caked into the carpet, and some oil or other stain on the other side. After the entire carpet was removed, scraped off the glue then sanded back to wood surface, then replaced the floor...box is back in order.
The drawers roll all the way out and are stopped by a fat rubber washer on the top of the box that meets with the top back of the drawer. Keeps the user from pulling the entire drawer out.