This foot can be set to sew on each side of the zipper. The edge of the foot guides the zipper to ensure straight placement

Janome 

Memory Craft 10000, Memory Craft 10001, Memory Craft 11000, Memory Craft 5000, Memory Craft 5700, Memory Craft 6600, Memory Craft 7700, Memory Craft 8000, Memory Craft 9000, Memory Craft 9500, Memory Craft 9700, Memory Craft 9900, Memory Craft Horizon 12000, Memory Craft Horizon 14000, Memory Craft Horizon 15000, Memory Craft Horizon 8200, Memory Craft Horizon 8900, Memory Craft Horizon 9400, Skyline 5, Skyline 7, Skyline 9