This is an insert for the Dewalt 20 compartment organizer (https://www.homedepot.com/p/DEWALT-Plastic-20-Compartment-Pro-Small-Parts-Organizer-DWST14830/301869332).

I got tired of small items such as washers or small nails sliding underneath the dividers. I made this little insert that fits into 1 of the compartments to prevent small items from moving around.