FWIW the item is a lensboard for an Omega DII or D2. It has the little bracket for the swingout red filter paddle and a lensboard insert for use with a 75-80mm enlarging lens when in the "bowl-down" mounting or in the "bowl-up" position it could be used with a shorter-than-normal focal length lens to make extreme enlargements of a small area of a negative without having to punch a hole through the darkroom ceiling.
