Westalee WF-FOOT- Metal Ruler Foot w/o Templates, Specify LS Low Shank, MS Medium Shank, HS High Shank, HSS High Shank Special, Singer Slant, Longarm

If you do not know what shank your machine is, all you need to do is lower your foot and then measure the height of the centre of the hole for the screw from the needle plate.