This TRUECUT 360 blade cartridge is a replacement unit for the TRUECUT 360 Circle Cutter when you need a fresh cutting edge. It comes ready to insert into the cutter and includes an attached safety cover to reduce direct blade handling during changes. Swap the cartridge when cuts start to drag, then store the spare in a dry place to keep the blade protected and ready Keep the cover on until the cartridge is seated in the cutter.