This is an alternative to the other packout inserts that follow the contour of the interior of the organizer. It is based off of the bins that go inside so when the lid is closed it keeps the bin from moving around. It is also a snug fit so it shouldn't move much with the lid open as well. This one is for model number 48-22-8435. This one also gives you the ability to stack two trays into one box for more organization if printed with the top tray.