This is a tube petzval, probably off an old magic lantern. It has a 'flap' lid that I removed but will include it if you want it. Focal length is 8 1/2", approx f4.3. Covers 4x5 at infinity and might cover 5x7 at portrait distance- I'm extrapolating from the image circle on my 8x10 ground glass. It might have darkened corners. Lens is a little over 5" high. No flange. Tube is about 60mm wide. The part that looks like a flange is actually the front of the lens. That's is where the 'flap' cover would attach if you used it. Glass was cleaned just yesterday and looks good. Slight cleaning wisp on the front but nothing that would affect a shot. My digital is giving me fits. The glass is, of course, round. And the actual 'flap lid' is black, not that you could tell from the photo... $110 shipped in the USA, USPS Priority insured. USPS money order preferred but Paypal is ok as long as you pay fees or send it as a 'gift' so there are no fees. % to APUG if sold here.