This Propeller Adapter includes the collet, drive washer, plain washer, and nut. Suits 4mm shaft. The Propeller Shaft diameter is 8mm, the collet length is 32mm, has a M4 shaft thread, and a drive washer face with a 20mm diameter. It is compatible with the E-flite ElectroStreak 1.1m RC airplane (EFL13350, EFL13375).