Simpson Manufacturing Co Inc is a manufacturer of wood construction products. The company offers connectors, truss plates, fastening systems, fasteners, prefabricated lateral systems, concrete construction products, adhesives, mechanical anchors, carbide drill bits, powder-actuated tools, and fiber reinforced materials. Simpson Manufacturing markets its products to the residential, light industrial, and commercial construction markets as well as the remodeling and do-it-yourself markets. The largest end market is the United States.