From the designer:

This is a custom insert that I have designed to fit your Milwaukee Packout to store your Dewalt Multi-tool and accompanying kit. It specifically fits the Milwaukee 48228435 PACKOUT Compact Organiser.

The specific Dewalt Multi-tool that this is designed for is model DCS355-XE, link is provide here: https://www.dewalt.com.au/product/dcs355n-xe/18v-xr-brushless-oscillating-multi-tool-bare-unit?tid=573286

It should also hopefully fit the DCS356N-XJ model. I was able to do a rough test fit at the local tool shop. You can see the comparison photo in the gallery above. I was unable to do a proper test as the tool skin had a tag on it, but it still slotted into the 3D printed insert.

https://www.dewalt.com.au/product/dcs356n-xj/18v-xr-brushless-oscillating-multi-tool-1-x-5ah?tid=573286

We now offer latches to identify which tool is in which case.  Latches are offered at a discount if purchased with a matching insert.