Here for you is a fine Goerz Dagor a classic and long lived lens design from a number of makers, this example from the original maker C.P Goerz the serial number equates to the 1920's. With F6.8 aperture and 210mm focal length and covering 8x5 (5x7) wide open and 8x10 at smallest stop, with excellent sharpness contrast and that Dagor goodness.