This is a telephoto lens converter, stored in a transparent plastic 'clam-shell' case, "TEL" in hand-written in red ink (faded) on the top of the case. There is a circle of yellow foam in the case, under the lens. The bottom, exterior of the case is marked "MADE IN JAPAN," in raised letters. The telephoto lens converter optic is covered front and back by black plastic lens caps. The rim around the front of the lens reads, "TIFFEN TELEPHOTO CONVERTER 1.5 X 37mm Made in Japan"
1.5 X 37mm
Located on rim of lens front
Located on interior of bottom (smaller) lens cap. Denotes size of cap interior
Located on interior of top (larger) lens cap. Denotes size of cap interior