These gears are engineered for fan drives in a cooling tower application and meet all AGMA (American Gear Manufacturers Association) and CTI (Cooling Technology Institute) standards. Housings are cast iron for strength and for effective dampening of noise and vibration. Gears are precision machined from nickel alloy steel, case hardened, and lapped in pairs. Bearings are selected for a minimum L10 life for 100,000 hours.