I think this lens was originally adapted for Exacta, but I took apart the helical, which didn't work so well anyway, and discovered that the focusing tube slipped perfectly into a long Bronica S2/S2a/EC/EC-TL extension tube (which screws into the Bronica helical or bellows), so I gaffered it in place and taped over any open screw holes and used it as a portrait lens for a number of years. I don't have the original mounting flange or helical. Now I tend to do these kinds of portraits in large format, so I don't really need this one anymore. The lens is hazy, and though Heliars are theoretically easy to clean, this mount seems pretty much stuck, so if you're good with solvents and lubricants and whatever is needed to dismantle the mount, you can clean it and maybe put it into a shutter for large format. Otherwise, consider it a portrait lens and the haze isn't too harmful. This photo was made with this lens, somewhere in the neighborhood of f:16, mounted on my Bronica S2a-- http://www.davidagoldfarb.com/photo/imng2003.htm Since this is something of a project lens, despite the legendary allure of the Heliar, I'm happy to let this one go for a modest $100, shipped in the US, +$10 for Canada and Mexico, +$25 elsewhere. PayPal, checks, money orders in US dollars all good.