Parker Hannifin started out in 1917 as Parker Appliance, selling pneumatic brakes. Through the acquisition of branded components, the firm has expanded into aerospace engines, agricultural and construction machinery, freight and passenger vehicles, and industrial automation equipment. Within these larger systems, Parker sells a wide array of small, critical pieces such as hydraulic, electromechanical, climate control, and filtration components. Many of its products are designed to work together, resulting in a high rate of cross-selling.