This Square D 9038DG9 float-operated mechanical alternator for use with water, hydraulic oils, and corrosive fluids switches between duplex condensate pumps within one closed tank. It has a NEMA 1 enclosure for protection and contacts that close on liquid rise. This mechanical alternator has a 4-11/16" maximum water level change post. Square D switches are manufactured by Schneider Electric. Square D brand pressure, float, and limit switches have been synonymous with safety, quality, and reliable performance for over 100 years. First launched by Detroit Fuse and Manufacturing in 1902, the Square D brand and its products continue to earn customer trust today.