A mount for the Park tool bike repair stands to allow you to attach Harbor Freight magnetic parts trays. The bottoms are recessed to allow you to hang wrenches and such from the bottom of the tray while you're working. The 4 inch parts trays can often be had free with any purchase if you can find the appropriate coupon, meaning you can setup the 2 tray mount for the cost of a couple of snap off razors (like 59 cents each).

The smallest tray holds one 4 inch parts tray from Harbor Freight.
The second tray holds two of the same parts tray.
https://www.harborfreight.com/4-inch-magnetic-parts-tray-90566.html

The third tray holds the larger 9.5 inch magnetic parts tray from Harbor Freight.
https://www.harborfreight.com/9-1-2-half-inch-magnetic-parts-tray-with-hood-97801.html