uxcell&reg; 4mm Airplane Propeller Prop Saver Adapter for Shaft Brushless Motor Product Name : Propsaver;Shaft Hole Dia. : 4mm/0.16" Total Size : 11 x 10mm/0.43" x 0.39"(D*T) Color : Orange, Silver Tone, Black Weight : 6g Package Content : 1 x Propsaver, 3 x Rubber Adapter Rings