Dave Brown adapter nut is constructed of plain black, CNC machined steel. Use with 2-1/2" 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:YS .90-1.2 4-Stroke, Enya 1.2R 4-Stroke, OPS Super .60and .61 5-Port.
Although it will depend on the thickness of your prop and the spinner size, as a general rule, always use the longest adapter nut possible."