5.5 Frame Diameter. MOTORS® brand pool and spa motor Nidec Motor Corporation manufactures. Built-in, industry-leading features like angled terminal boards for convenient access… Voltage selection with the flip of a switch… No-worry switches with no field adjustment needed… All help to make installing and maintaining these pool and spa motors much faster and easier than the competition. Shaft Threads – 1/2-20 UNF-2A. 300 Series Stainless Steel Shaft. Voltage Selection Device (Dual Voltage Only). NOTE: Total Horsepower (Horsepower x Service Factor) of replacement motor must meet or exceed current pump motor.