I have managed to accumulate the three differently marked Gillette Rocket 'Flare Tip' varieties as well as examine & shave with them. They are marked under the heads either 'A', 'S' or 'II' respectively. The only differences noted are between the 'S'' marked one and the other two. The 'A' & 'II'...
My grandad was born 1890 and died 1965. He hated shaving. His face was a mixture of stubble tufts, cuts and toilet paper patches. I loved the old guy dearly but would never have to do with his shaving kit!!