I just used a Personna Red in my Gillette Tech from 1962 on Saturday in the shower. I had forgotten how good they get after the first shave.I think personna platinum(reds) is the blade I have tested in the most razors, they work great in every one for me aggressive mild it doesn't seem to matter too much. Tatra platinum is my 2nd pick and nacets probably third. I like gsb better, but nacets seem less sharp to me, so they are more versatile.