how do i even know if it takes m2? I don't have the box
Place it into the M2 Slot. Either search for M2 slots on Google images, or keep trying to place the M2 in each slot on the card reader. Eventually you will find the right one because it fits snugly into place.
You should see the product manual. I have 25 in 1 card reader, but I don't think it supports small cards like M2 or MicroSD. Usually its for different cards from cameras.
