Motor Specifications 120 volt A.C. 1/40th horsepower one speed 1550 R.P.M. Rotates clockwise looking at shaft. Motor is 3-3/8 diameter and 2-3/8 long. The shaft is 5/16 inch diameter. Bolts are on a 2-7/8 inch diameter circle. Blower Specifications 5-1/8 Diameter and 2-1/2 inch long. 5/16 diameter bore The size of the blower matches the power output of the motor very well. Note: This motor and blower combination was used on a lot of Miami Carey and other brands of bathroom fans and range hoods back when gasoline was 25 cents a gallon.The quality of those range hoods makes them very popular to this day. Great engineering! Note the compact nature of the blower and the great way to cool the motor.