This 18" replacement blade is made from high carbon quality steel for use with the Martin Yale 620RC cutter. For the best performance from this cutter it is recommended that the blade be sharpened after 600 cuts. It's important to always have replacement blades on hand so work flow is not interrupted while the blade is sent to be sharpened. Always use extreme caution when handling or replacing the cutter blade. Please note - if purchasing this blade for an older or used machine, please include the year or serial number of the machine as blades can vary by year. Please call us if you need assistance.