A Leitz microscope accesspry storage box from the 1950's/ 1960's. It is in very nice condition for its' age. I dont have a clue what accessory this box would have housed. The latch and hinges are in perfect operating condition. Someone has written E T C on the underside in black marker. A kind Ebay member sent me this information: " This is almost certainly for a filar micrometer ocular. The rectangular housing with the micrometer slide would rest in the flat cutout, and the two circular cutouts would support the ocular end and the lower sleeve of the eyepiece. They are offset because there is a micrometer drum on one side of the rectangular housing." You will not be disappointed with your purchase! Thank you for looking!