This is a Darlot Single View landscape lens. It is a meniscus with a front aperture wheel. You can see it on this image below from Dan's website with an old Darlot catalogue on it. This one is a 1-3 for 9x7. To me, these types of lenses are more interesting if you take the glass out of the barrel and use them wide open. You get cool soft glowing highlights and a soft look, since they were meant to be used stopped down to f16 or more. This one looks to me like it easily covers 8x10 even in the barrel.
Approx 3" tall. Includes the flange. 9 1/2" focal length, diameter at flange approx 3 1/2". Glass is good.
Asking $200 + $10 USA shipping; Paypal, USPS money orders, checks from people I know. Free USA shipping for USPS money orders or check. $$ to APUG if sold here.