Doosan Infracore America, Suwanee, Ga., has added four new excavators to its line of heavy equipment: the DX300LC, DX340LC, DX420LC and DX480LC. Each new model in the DX series of excavators (Circle 902) is known for strength and durability, and feature a newly designed electronic package that allows communication between the engine and hydraulics for optimum performance and fuel economy, while a dual-walled exhaust silencer reduces noise levels.