This handy mig welding nozzle reamer is adjustable to fit any size or brand of mig nozzle. It will remove even the most stubborn bits of slag from blocking your arc at the welding nozzle. The red portion of the welding nozzle reamer moves in a horizontal motion. Moving the reamer body forward encloses the blade for entry into the nozzle opening. Then move the nozzle reamer body back to release the blades & turn the back knob. This makes the blades move in a circular motion to remove slag.