Designed to slide into field erected or factory built air handling units or plenums, TEK Plenum Fans operate by pressurizing plenum in which they operate, and are suited for supply or return air applications. Impellers are constructed with injection molded GRP polyamide TEK wheel and offer non-overloading power characteristics. Equipped with TEFC industry duty motors, modular fans eliminate traditional scroll housings, transitions, and diffusers.