Excellent choices for aggressive applications where metal blowers quickly corrode. Metal blowers rely on protective coatings, which develop pin holes and pores. Corrosive vapors seep through and attack the metal, causing failure. The smaller laboratory units have round inlets and outlets and industrial units (37132) have round inlets and rectangular outlets. A range of sizes designed for use in lab hoods and cabinets to more industrial applications. If installing your own motor, note that Norton® blowers must not exceed the stated RPM of each blower. NOTE: Blowers are supplied fully assembled in counterclockwise upblast position. For indoor and outdoor use. All outdoor vertical blower discharge ducts must have weather hoods. No bottom horizontal or down-blast positions. Great where applications include corrosive vapors, dirty, damp or oily service. Direct drive motor is more compact, single speed, fewer moving parts and no field adjustments. Other options and a full line of replacement parts available for special order upon request; please contact our quotes department at 800-335-6809 or firstname.lastname@example.org.