I have one!!! This is a pressure foot to make gathers evenly. I used mine all the time when I sewed for my girls.A piece of fabric feeds along the bottom then you can put a piece on top and let the loose forked part of the foot feed in the second fabric ,it will gather and sew down at same tine. The adjustments are the top part with 1- 2 or 3 marked on it .I hope this helps.