I have, for sale, American Optical AO Spencer 160mm tub length 10x and 20x dark medium phase contrast objectives with matching condenser annuli. Please visit my eBay page for photos and details, thank you:
https://www.ebay.com/itm/154978042295
https://www.ebay.com/itm/154977996120
I also have an AO 160TL 20x dark medium phase objective without matching phase annulus for sale:
https://www.ebay.com/itm/154787604908
American Optical AO Spencer 160TL 10x and 20x phase objectives with matching condenser annuli
Moderators: rjlittlefield, ChrisR, Chris S., Pau