The first Yashica SLRs with the then new Contax/Yashica (CY) bayonet mount were the FR, FR I and FR II SLRs. While they were intergrated into the Contax SLR system, these bodies were exceptionally clean "no fringe" cameras, reduced to the max so to spealk. The FR was fully manual, the FR I had both a manual as well as an aperture priotity AE mode, and the FR II had only the AE mode (no manual exposure). All these cameras could be used with the corresponding winders and even the motor drive of the professional Conatx RTS. While it wasn't advertized by Yashica (the manufacturer also of the Contax RTS), it certainly wasn't "by chance" that the FR / FR I / FR II SLRs were equipped with the corresponding connections.