The 927 miter gear is used when the operating shaft must be carried down at a right angle to the damper shaft. Often the 927 miter gear is used with a model 301 or 315 ceiling regulator and a 3/8″ square rod to control a damper above a ceiling. Damper shaft can be either 3/8″ square or ½” round. Four ¼-20 mounting bolts and nuts are supplied with each set of miter gears. Contact the factory to accommodate shafts in other sizes.