Thanks to its narrow, centrally positioned toe, Zipper foot #4 can stitch very close to the zipper coils, allowing it to sew the zipper on neatly.
Tips for BERNINA Zipper Feet - WeAllSew
Using a Bernina Invisible Zipper Foot :: - SewKatieDid
54N - Non-Stick Zipper Foot, Bernina #0084797500 : Sewing Parts Online
Gina's Pro Tips - Bernina Presser Foot 35 Invisible Zipper
Foot Feature: Bernina #4 Zipper Foot
4 BERNINA Zipper Sole - Bernina - 0327127100
Foot Feature: Bernina #4 Zipper Foot
Draping a Custom Dress, Part Five: Final Garment - WeAllSew
Bernina Zipper Foot With Guide 0329647200 14D Genuine 9mm