I have a different, smaller one, probably much less $$ as well. It isn't that effective IMHO. It requires taking out the dull blade, inserting it in between 2 emory disks and turning, turning, turning, change and do other disk, then reinserting. Nicked myself a time or two, not worth the effort. I buy the much discussed Harbor Freight blades and have been happy. Cheap enough to toss out when dull, or use for paper. Like needles, a bad blade isn't worth keeping around, but not so expensive that I can't have a good supply and change when necessary.