uxcell RC Airplane Helicopter 2mm to 4mm Brass Motor Shaft Coupling Coupler Product Name : Motor Shaft Coupling;Type(Inner Hole Dia) : 2mm to 4mm/0.08" to 0.16" Total Size : 2 x 0.9cm/0.79" x 0.35"(L*D);Thread Dia : 2mm/0.08" Main Color : Gold Tone;Material : Brass Weight : 5g Package Content : 1 x Motor Shaft Coupling4 x Install Screws