Genuine Olfa rotary blades guarantee quality and product life. Like all Olfa rotary blades, it comes in a robust tungsten steel to aide in edge retention. Able to go from fabric to paper without the worry of dulling your blade. Fits any Olfa 28mm rotary cutter; there will never be any issues with it fitting your older model cutter. The blades come in its own carrying case for easy and safe storage.