Donaldson Co., Inc. engages in the manufacture of filtration systems and replacement parts. It operates through the following segments: Mobile Solutions, Industrial Solutions, and Life Sciences. The Mobile Solutions segment is involved deals with replacement filters for both air and liquid filtration applications and filtration housings for new equipment production and systems related to exhaust and emissions. The Industrial Solutions segment focuses on industrial air filtration, industrial gases, industrial hydraulics, power generation and aerospace, and defense business units. The Life Sciences segment consists of bioprocessing, food and beverage, medical device, vehicle electrification, microelectronics and disk drive business units. The company was founded by Frank Donaldson Sr. in 1915 and is headquartered in Minneapolis, MN.

Fuel Tech, Inc. engages in the development, commercialization and application of proprietary technologies for air pollution control, process optimization, water treatment, and advanced engineering services. It operates through the following segments: Air Pollution Control, Fuel Chem Technologies, and Other. The Air Pollution Control Technology segment includes technologies to reduce nitrogen oxides emissions in flue gas from boilers, incinerators, furnaces, and other stationary combustion sources. The Fuel Chem Technology segment uses chemical processes in combination with computational fluid dynamics, and chemical kinetics modeling boiler modeling, for the control of slagging, fouling, corrosion, opacity, and other sulfur trioxide-related issues in furnaces, and boilers. The Other segment includes those profit and loss items not allocated to either reportable segment. The company was founded by Burr T. Walter in 1987 and is headquartered in Warrenville, IL.

Perma-Pipe International Holdings, Inc. engages in the design, manufacture, and sale of specialty piping and leak detection systems. Its products include industrial and secondary containment piping systems for transporting chemicals, hazardous fluids and petroleum products, insulated and jacketed district heating and cooling piping systems for efficient energy distribution to multiple locations from central energy plants, and the coating and/or insulation of oil and gas gathering flow and long lines for oil or mineral transportation. The company was founded on October 12, 1993 and is headquartered in The Woodlands, TX.