Hi. I read that Gillette 7 o'clock double edged blade works with double edge razors. Does this just apply to Gillette DE razors or all DE razors? I have a Merkur DE razor.
Also, does anyone have any experiences using these blades from Gillette?
The Gillette 7 o'Clocks work well in any DE razor, doesn't have to be a Gillette razor. You have to experiment what razor/blade combo works for you. Any DE blade works in any DE razor.
There are currently 4 or 5 variations of the 7 o'Clock. The most popular is the SharpEdge (yellow wrapper color) made in Russia. My favorite is the Permasharp (green) from India, which I find is a markedly better blade, but others have a different opinion. There's also a Super Stainless (green) from Russia and a Super Platinum (black) from India, which I find too rough and harsh.
You can read several opinions on the various versions of the 7 o'Clock in the review section.
+1 what Kevan said - each person will find their own blade and razor combo that works.
I have tried the Gillette Super Stainless green (from Russia) in a Gillette flare tip razor and my Feather portable razor and had horrible shaves both times.