Yes, I just got one of these and it does work. I had a blade in my 45mm cutter that needed a little help. It would cut OK, but I always had that one or two threads that it skipped. By the time I was done doing some cutting, it is good as new. I got the 6 1/2 x 12 and the price was around $17.00 or $18.00 dollars.
Can't remember what the cost of regular rulers are, but I do think they are worth it.