This design ONLY fits the Milwaukee 2 unit (48-22-8442). This is the ultimate modular storage solution for your Packout Drawers!The specific tool the insert is designed for: https://www.milwaukeetool.com/Products/2723-20 Modular Design – Battery Storage Options: The design allows for storing a 5ah battery. If you don’t want to store a battery in your insert, you have the option to store your dust extraction mount in the battery tub should you chose. The default spot for the extraction mount has a hole in the bottom to allow it to rest on the bottom of the drawer and ensure the drawer can close as it would be too tall otherwise. As such, a small cover is provided that allows you to cover that hole in the event you want to use that spot for general storage. You can see a demonstration of this in the gallery above (the image is captioned as “Storage Options Demo.”