The Spencer multistage blowers are efficiently engineered to deliver excellent performances in an array of air and gas applications. They are useful in commercial, industrial, municipal as well as institutional installations. The blowers are available in a vast spectrum of models and versions, providing diverse features. There are three basic versions. The SOH model is conventionally overhung and has an extended motor shaft. The impellers are fitted onto the motor shaft. The 4BOH version has four-bearing overhung and its impellers are fitted onto a shaft that is conjoined with the motor shaft. The 4BOB model is a four-bearing outboard and its impellers are fitted onto a shaft that is supported at its ends by ball bearings that self-align. This shaft is joined to the motor shaft. The 4BOH and SOH models incorporate the trademarked sugar scoop design. Blowers equipped with the sugar scoop design are instantly recognizable as being genuine Spencer products. These models from the Spencer stable have been around for decades. The superlative quality has endured for years, spanning a century and more.