This is the HyperFlow 370 EP Ducted Fan Rotorblade. This is the Rotorblade for the HyperFlow unit with motor and for the HyperFlow unit without motor (GPMG3910). FEATURES: Black plastic construction The rear of the rotorblade accepts a 8mm hex hub INCLUDES: One rotorblade SPECS: Outside diameter: 2" (51mm) Center hole diameter: .11" (3mm) ajw 8-6-06 ir/jxs