I have had this for years and shaved with it today. I recall something looked odd about the knurling back then and it caught my eye. Sort of a mix between vanilla Super Speed and a Flare Tip, minus the vertical grooves. It didn't draw much attention on the auction site. Not sure how rare it is but I haven't seen another one. Smooth action and comfortable result. This one is marked Y-1, 1953, from Brazil.