This is a small neat filament cleaner that is sculpted to sit well on the top of the M3D Micro's print head. The small amount of drag it induces is inline with the filament feed, so that doesn't drag at the head as it moves. Just cut a cube of foam a little larger than the cleaner, and press it in. The first time you use it, cut the filament at an angle so that it is pointed, and use that to bore a hole through the foam. The filament enters the cube on the side that has no cutout, and the cutout sits around the cable that exits the Micro's print head.There are two versions of the STL. I suggest you print the scaffolded version without support switched on and then remove the scaffolding with needle-nosed pliers or similar. Cut a cube of foam a little larger than the cleaner, and press it in. The first time you use it, cut the filament at an angle so that it is pointed, and use that to bore a hole through the foam. The filament enters the cube on the side that has no cutout, and the cutout sits around the cable that exits the Micro's print head.