Has anybody ever heard of or tried Graham-Field prep blades? I just got a box of 250 for ~$30. No printing on the blades, single generic white wrapper, plain unmarked cardboard box. These are made for the medical field for surgery prep. I may not get around to them for awhile & can't find much about them. 1/2 the price of Personna med preps and cheaper than GSB, but I don't have any idea how good (or bad) they are.