They are made out of carbon steel and are designed with a universal opening so they will fit on other 45mm rotary cutters.
This can vary from person to person and how one uses their cutter, as well as the type of cutting mat they have. The blades have been tested at various fabric shops in Toronto, and after using them for up to 8 hours a day, five to seven days a week, each shop got between 3 - 4 months of use from one blade!
Please note: the blades are coated with oil to keep them protected from humidity during transportation. We recommend wiping them off with a scrap piece of cloth before use to avoid staining your project.