with the guys above, I use polsilver SI in both my Techs and get great results, both are not so keen with 7 o clocks (green in my case)I am not getting along with my newly acquired English flat bottom Tech Two shaves in with a Gillette 7 O'Clock Yellow and I'm getting nicks and irritation on my neck. Will need to try with a different blade and try that blade in a different razor.