As far as I can tell S. B. Kahnweiler & Co NY was an authentic American-made razor/cutlery brand, not something that was made or supplied from another part of the world and then rebranded, US makes are S. B. Kahnweiler & Co, The Camillus Cutlery Co, Torrey, Worcester, Genco, Enterprise and Keen Cutter, and they all shave very nice, I am yet to find my favorite amongst them, but part of the fun is trying yourself, so don't hold your breath for my opinion!
This razor weighs 39 grams and has a spine thickness of 3 mm, blade height of 15 mm, or around 1/2 that delivers a bevel angle of 11.5 degrees. The razor has been used a bit and the edge and spine has some wear on it, the point has also been adjusted to remove a crack on the toe, but it has some vintage porn on the side of the blade and some pretty cool scales going for it, so it will surely find a home! The razor is shave ready and easy to hone and strop, it has lots of life left in it, look after her!
*Vintage razors are priced according to model and availability, time spent cleaning and reconditioning and time/level of honing. Please enquire if you need additional work done to this razor prior to purchase. All straight razors will require a stropping on a leather strop before every use. Pics are unedited (detail) and provide a true image of the condition of the razor.