This is a 2-3/4" (70mm) 2-Blade Spinner by Dave Brown Products Incorporated. FEATURES: Aluminum construction INCLUDES: 2.75" (70mm) aluminum spinner with backplate, 31 x 4.75mm allen screw four plastic bushings REQUIRES: Long prop adapter nut depending on brand and size of engine; DAVQ9428 L428 Adapter Nut Long 1/4-28 fits O.S. .25-.60, Como .19-.61, Enya .25-.53, Fox .19-.50, HP .21- .61, Irvine .20-.61, K&B.19-.65, OPS .40-.60, Peco .21-.45, SuperTigre .25-.60, Webra .28-.80 DAVQ9524 L524 Adapter Nut Long 5/16-24 fits O.S. .61-.90, SuperTigre .61-.90, Como .75-.90, Fox .60--1.2, HP 1.2 4-stroke Not Carried L610 Adapter Nut Long 8x1mm fits Enya 1.2R 4-stroke, HP 1.2 4-stroke, OPS Super .60-.61 5 port, YS .90-1.2 4-stroke DAVQ9710 L710 Adapter Nut Long 7x1mm fits Enya .35-.60, .60-1.2 4-stroke (non-R) engines DAVQ9810 L810 Adapter Nut Long 8x1mm fits Enya 1.2R 4-stroke, HP 1.2 4-stroke, OPS Super .60 .61 5-port, YS .90-1.24 4-stroke DAVQ9812 L812 Adapter Nut Long 8x1.25mm fits OPS Maxi .30, Peco .60-.80, Rossi .40-.61, Webra .61-1.2, all YS 2-stroke Dave BrownPart DAVU227