7/16" serrated butterfly/throttle stop. This butterfly/throttle stop fits the 7/16" serrated shaft that Buzzard and late model Bird catcher injectors as well as most carbon fiber injectors use. With these throttle stops it makes it easy to set your idle and have a butterfly stop so that they don't rotate over center.
Throttle stop includes stainless hardware and thumb wheel to adjust idle. Billet stop is black anodized and made from heat treated billet alum. Stops are sold each.