3D printed adapter for the bay-1 bayonet mount, used for example with most f3.5 Rolleiflex, Yashica TLRs, among others.
Not compatible with Rolleiflex f/3.5 Planar and Xenotar models, as those use the bay-2 bayonet.
Please note that on the bay-1 mount of the Minolta Autocord the adapter will not fit properly.
The 3D model file is also available for free at Thingiverse