I own a Bernina 830, 880, they use the same bobbin. I also own a 590 and 790, they use the same bobbin. I understand the Bernina 4 series uses the same bobbin as the 5 and 7 series. The 4,5, and 7 series bobbins hold more thread than the 8 series. The feet for these machines are interchangeable. My 5,7 and 8 series all have the BSR and I don’t know if the 4 series has BSR. They also have the dual feed feature that I use all the time, again I’m not sure about the 4 series.