uxcell Gasoline Engine Clutch Parts Collet Coupler Shaft 3.18mm to 4mm Product Name : RC Boat Collet Coupler Shaft;Thread Size : 7mm x 4mm/0.28" x 0.16"(D*L) Collet Hole Dia. : 4mm/1.25";Untheaded Motor Shaft Dia. : 3.18mm/0.16" Total Size : 22 x 9mm/0.87" x 0.35";Materials : Stainless Steel Net Weight : 9g Package Content : 1 x RC Boat Collet Coupler Shaft