Dave Brown X-Long Adapter Nut 5/16-24 DAVX524 Dave Brown adapter nut is constructed of plain black, CNC machined steel. Use with 3-1/4 to 4" spinners and under. This prop adapter kit tightens the backplate and propeller onto the engine, then using a single bolt-on design, holds and centers each spinner perfectly on its baseplate. Will fit the following engines: OS Max .61-.90, SuperTigre .61-.90 and G2300 Fox .60-1.20.Although it will depend on the thickness of