GEARYTE CERAMIC UTILITY KNIFE replacement blades are razor sharp and will cut through standard packaging materials with ease. Strong, long wearing Zirconia Ceramic material stays sharp even after extended use. CERAMIC BOX CUTTER REFILLS will stay sharp up to 10 times longer than a steel razor blade. Ultra strong Zirconium Oxide (Zirconia) ceramic will not spark or rust, making it a safer option than other blades in some applications. GEARYTE CERAMIC UTILITY KNIFE blades will cut through tape, paper, cardboard, plastic and nylon and fiber strapping materials with ease. CERAMIC UTILITY BLADES will keep an edge longer than a steel blade but are also easier to break under stress. It is advised that you only use ceramic blades for cutting and slicing only and do not use them to pry things or use the blade as a screwdriver or chisel. GEARYTE CERAMIC BLADE box cutter and utility knife blades refills come in a reusable plastic case that provides protection for the blades and a convenient storage option. Gearyte utility replacement blades can be used in many types of knife handles, from straight box cutters, to folding style cutters and to EDC knife handles that accept a utility blade replacement.