KNIVES -Our auto retractable safety knife has the advantage of a full-sized handgrip which allows for accuracy and control. -The retractable blades make sure that you are always working with the sharpest edge. -The blade slides easily in and out with a blade locking feature. -Our snap off knives are ideal for precision cutting of a variety of materials. REPLACEMENT BLADES -Replacement cutter blades for 18mm Heavy Duty Cutter knife & 25mm cutter knife. -Snap off section when blunt to form new cutting point. -Heat Treated for long life.