Used Multistage Blower. This Four-Bearing Outboard (4BOB) blower is multistage centrifugal unit which handles air and other gases, working either as blower or exhauster. It increases the pressure of the incoming air or gas by guiding the air or gas from one stage to the next through diffusers. It is centrifugal because the flow through the blower is turned perpendicular to the axis of rotation. Operating temperature: inlet end 165 F (74 C), outlet end 150 F (66 C). Pressure up to 20 PSIG and vacuum to 15" Hg. The motor is missing from this unit.