Stay away from no-name-shoulderless blades (nothing wrong with vintage shoulderless so don't get me wrong).
Some private sellers try to pass them off to unsuspecting buyers, with carefully worded descriptions hinting vintage, like “with original box” and “I don’t know the age”. But in all cases they cannot tell you the name of the manufacture and as usual no close-ups.

I think SRP has a list of brands to stay away from.