This only is made to hold the batteries that do NOT have the brick on the end of the M12s. Just a caution. I wanted something that could hold several batteries and be like an M18 6 battery holder I saw way back when. I am sorry if it's rough, I am new to the design aspect of things :) I do not really know the rules but someone I know told me it may help other people and I figured I would at least get the concept out there for someone to do better! P