Sewing zippers in no time. Accurately sewing in zippers of all sizes. For 9 mm machines with BERNINA Dual Feed system Designed for sewing close to zipper coils while simultaneously feeding the fabric evenly and smoothly. Zipper foot #4D works with the dual feed feature found on some BERNINA models to feed the fabric and the zipper tape at the same pace so there is no shifting or sliding as they go under the needle. #4 works with all machines and #4D works with machines with the Dual Feed function Compatibility. B 570 QE/QEE, B 590, B 710, B 740, B 750 QE, B 770 QE/QEE, B 790, B 790 PLUS, B 780, B 830, B 880, B 880 PLUS.