Torque amplifier: Used to tighten the "Jesus" nut on a helicopter rotor head. It uses the gear down principal to amplify torque, depending on specs. A 1:20 will produce 20 lbs of torque for every 1 lb applied IE 100 lbs in = 2000 lbs torque. Thanx Lloyd Godsey kk7iz at cox.net 480-620-7145