If I could find my Martelli I'd let you know..... I do know that I have had my Martelli for a couple years, use it occasionally, and have never put a new Martelli blade in it. I have only used Olfa blades (cheaper with Jo-anns coupons) in all of my cutters. The HF blades fit in my other cutters, so am assuming that they will fit the Martelli.