5mm Flexible DC Motor Hex Coupling Coupler Copper for RC Model Wheels Product Name : DC Motor Hex Coupler;Material : Copper Color : Gold Tone;Total Size : 18 x 12mm/ 0.71" x 0.47"(L*Max.W) Fit Motor Shaft Diameter : 5mm/ 0.2";Hex Hole Diameter : 3mm / 0.12" Screw Fixed Hole Diameter : 2.5mm/ 0.1";Weight : 15g Package Content : 1 xDC Motor Hex Coupler