This is a Two-piece Two-Blade White Nylon Spinner with a Nylon Backplate / for use on the Hobbico ElectriStar Trainer, HCAA12**. / / INCLUDES: One spinner cone / One backplate / Two 1/8 x 1/2 S/T screws / / SPECS: Spinner Diameter: 2-1/4" / Spinner Backplate Thickness: 3/16" / Crankshaft hole: 5/16" / / JiM 3.29.07 / ir/jxs