Poggi 2020 Concentric Shaft Reversing gearboxPoggi Concentric Shaft Reversing gearbox 2020 Series. 1: 1 ratio with ability to select output rotation via simple to use selector. Aluminum alloy housing featuring fully machined flanges with threaded holes. Hardened, tempered and ground alloy steel shafts supported by electric motor grade deep groove ball bearings, Gleason spiral bevel gears made of hardened, tempered and ground alloy steel for silent and efficient operation in either direction.