A Gridfinity compatible 2x2 holder for Milwaukee batteries that even lets the batteries lock into the model. If you use the standard 6mmx2mm magnets in the holes provided they should be strong enough to hold this in place on the base plate while the battery slides out, provided that you push the release buttons on the battery all the way in as you take it off. There is an overhang towards the top of the model that not all filaments will handle well, with PLA it did bridge okay for me and a hobby knife makes short work of any small drooping pieces. Happy Printing!