Early vintage Bakelite Yashica medium format twin lens reflex (TLR) camera push-on lens cap. Upper lens area is felt lined. This is for some models that came out before the use of the Rollei-spec bayonet system, not for any that take bayonet accessories. OD of your taking and viewing lenses should be about 32mm or so. 

WHO WE ARE: Oddog2 is a husband/wife team, home-based small business specializing in the buying/refurbishment/selling of primarily photographic equipment. We do occasionally have other types of things to sell that come to us as a result of our search for camera-related items. We have 47 years of experience (22 years as a hobby, 25 as a full time effort) with photographic equipment, both as a shooter (17 years newspaper photojournalist) and as a collector/restorer/seller. We have been on eBay as Oddog or Oddog2 since September 1999.