21 Series Motor Bi-Rotational Tandem Unit 2 Stages Sae 2/4 Bolt B Sec 7/8-13 Spline Shaft With OB Bearing First Stage 2 Gear Width Gear Housing Orb #20 Inlet PortOrb #20 Outlet Port Bearing Carrier Blank Inlet Port Blank Outlet Port Second Stage 1 Gear Width Gear Housing Blank Inlet Port Blank Outlet Port Port End Cover Orb #12 Rear Inlet Port Orb #12 Rear Outlet Port Extended Studs Top