DH wanted to try my 45 rotary cutter on some foam, it didn't work, but I knew it was a good idea to change the blade. I have some packs of Harbor Freight blades and I thought it was time to try them, but I wanted to know that it was one of those blades in my cutter. I had a selvedge edge wrapped around the handle and tied as a leash so I took a pen and wrote both the date and the initials HF so I would know both things....and now I will, even if I don't remember it without looking.