Fiber optic cable blowers are designed for the installation of fiber optic cables with diameters from 5.8 mm to 28.7 mm into inner ducts from 25 mm outer diameter to 50.0 mm outer diameter. It provides maximum clamping force on the cable of 80 lbs / inch (14.3 kg / cm) at a hydraulic pressure of between 550-650 psi (39 kg / cm2 to 46 kg / cm2). A lower clamping force would allow the cable to slip under the tractor drive earlier, thereby reducing the pushing power of the machine. On small diameter fibers, relative to the diameter of the duct, it is recommended that the pushing force be lowered to reduce the potential for folding the cable over in the duct.