Looking at the Wiki I figure it is a Gillette old type, single ring, thin cap. That Wiki has a ton of info in it, even serial numbers by year. That's how I figured out it was made around 1921 which is also about the time my Grandfather would have started shaving on a regular basis.
Thanks Jeffer, I'll research them and keep an eye out for a good one.
That's so awesome to have such a special razor like that, congrats!