McGrath RentCorp operates as a business to business rental company in the United States and internationally.

It rents and sells relocatable modular buildings, portable storage containers, electronic test equipment, and liquid and solid containment tanks and boxes.

The company operates through Mobile Modular, TRS-RenTelco, and Enviroplex segments. The Mobile Modular segment rents and sells modular buildings designed for use as classrooms, temporary offices adjacent to existing facilities, sales offices, construction field offices, restroom buildings, health care clinics, child care facilities, office spaces, and various other purposes; and portable storage containers.

The TRS-RenTelco segment rents and sells general purpose electronic test equipment, such as oscilloscopes, amplifiers, analyzers, signal source, and power source test equipment primarily to aerospace, defense, electronics, industrial, research, and semiconductor industries.

It also provides communications test equipment, including network and transmission test equipment for various fiber, copper, and wireless networks to the manufacturers of communications equipment and products, electrical and communications installation contractors, field technicians, and service providers.

The Enviroplex segment manufactures and sells portable classrooms directly to public school districts and other educational institutions in California.

The company was incorporated in 1979 and is based in Livermore, California.