I have sold these rings for $10 each at camera shows over the years. I am no longer going to the shows though so I am liquidating all of my old stock on ebay at bargain prices. This is a buy 1 and get 2 FREE DEAL! These are top quality black anodized aluminum Step Up/Down Rings made in JAPAN. They are for mounting Series accessories such as filters, rings, or lens hoods on a your Vintage camera. Step up/down rings like this are a good idea. Filters can be very expensive so these rings save you a lot of money. The older Series rings like this can be hard to locate. I have a limited number of new ones on hand, once they're gone they're gone, get them while you can.