They are called carpet cutter blades, they come in 2 per pkg. for about $1.79. They only fit the 45mm rotory cutter, and they work great, just be sure and wipe off the oil that they have on them. And be careful, and make sure you use just one blade. You have to ask someone in the store to show you where they are at. The store has so many things in it...Hope this helps, you can also order on line.