Cabinet Drawer Slides

Cabinet Drawer Slides
Has anyone heard of a sliding tray (maybe plastic?) that fits inside a standard file cabinet drawer?

I worked at a place where the top drawer of the file cabinet had a small sliding tray that hung on the rails for hanging files. I could slide it back and reach to the bottom of the drawer. It held pens, paper clips, etc. It's like a standard drawer tray you'd find at an office store but can hang and slide in a file cabinet drawer. I can't find it anywhere at the office stores (Office Depot, Office Max and Staples) or online.

I know exactly what you are talking about because my desk had the same thing. Very handy. But, I recall that the sliding tray came with the desk. Maybe find out the manufacturer of your desk and go to that companys web site and see if they have what you are looking for.