A gorgeous early example. Glass on this just sparkles.
This is an f6 extra extra rapid Aplanat type. These lenses are tack sharp, but they've definitely got some un-explainable "vibration" happening at wide open. Super contrast with just a hint of 'buzz'.
Heck, I can't explain it. You'll just have to buy the lens and make some pictures. BTW there's some images on my web pages made with one of these (not this one).
Original flange is there, though it's been trimmed a wee bit. This was on a 3 1/2" Baby Deardorff plate when it came to me. I haven't been able to break the flange loose. Not important, it's easy to work with as it is. I'll let you do it. $385 + shipping