21 Series Motor Bi-Rotational Single Unit Sae 2/4 Bolt B Sec 7/8-13 Spline Shaft With OB Bearing 1-1/2 Gear Width Gear Housing Orb #16 Inlet Port Steel Plug Orb #16 Outlet Port Steel Plug Port End Cover Orb #16 Rear Inlet Port Orb #16 Rear Outlet Port Standard Studs