Vintage Rolleiflex Rolleikin 2 - 35mm adapter for Rolleiflex 2.8 in case.
Condition is commensurate with age.
Marks to film gate shown in pictures.
Felt interior of case is deteriorating and shedding red fibres (fibres can be seen for example on film transport teeth).
I confess that I've never used this and in fact don't even know how. YouTube and Internet University would be your best friend in finding out how to use this.