It's a control horn and if you don't have a local hobby shop you can order them online from Amazon, ( I mean really, WHAT can you not order from Amazon?) or many other internet sources. But these are laser cut 1/16 inch ply control horns, don't know where they got them. I've been using Popsicle sticks myself. Drill a hole in the round side, guesstimate the angle needed to put the hole over the hinge-line with the stick in the meat of the foam then I dig out the foam down to the far side paper, fill it with hot glue and then put the stick in and smooth the overflowed glue. Works fine for me. But the purchased ones do look cooler.