Classic Cave Zoom eyepiece from mid-late 1960's. Glass is excellent, few minor scratches on barrel, coatings look good, smooth "twist" operation (remarkable condition considering age). Don't know what these are worth, since few have surfaced over the years. Will take best offer/trade by Wednesday (2/5). I don't normally like to sell by "auction", but I honestly do not know what this is worth. Please make offer!