The US model number for the stapler that fits this insert is 2447

From the designer:

This is a custom insert that I have designed to fit your Milwaukee Packout to store your M12 Staple Gun and all your extra staples. It specifically fits the Milwaukee 48228435 PACKOUT Compact Organiser.

The insert consists of 2 parts, the first is the insert for the Staple Gun itself. I've also designed this Staple Gun insert to have a empty space underneath the tool where you can store back up backs of staples.

The second is an organiser insert for your extra staples and a spare battery. I have included files for 3 different variants of these devisers so you can pick which you prefer for your set up! Look at the second image above to see a render showing these variants.

Options:

Choose parts tray type.  The 2-divider tray is my personal favorite and can hold a larger format battery and still has room for organizing staples.  The 3-divider tray can hold a smaller format battery.  The single divider tray can hold 2 large format batteries.

Then, select a color combination!  First color is for the tool tray, second is for the parts tray.

Finally, we now offer latches to identify which tool is in which case.  Latches are offered at a discount if purchased with a matching insert and are sold by the pair.