This foot is very similar in design to the regular darning Foot #9.
However, its sole is open in the front for improved visibility. You can see the needle more clearly while stitching. Combined with Bernina's Hopper Mechanism, this foot gives excellent fabric control (no flagging) while the stitches are being formed as well as the ability to move the project freely under the foot.
When purchasing feet, please select which version of foot which fits your machine. The ‘standard’ version of foot fits older machines from the Bernina 910-1630. The ‘v version’ fits the newer Bernina machine models from the Activa 125 upwards.