Review on High-performance Ceiling Heater Motor - NuTone S57769000 by Wayne Ohlrogge

As several people have pointed out the 'plug' is actually two ring protrusions but that was fine as the original was attached to the heater box so it was really straight replacement for the original. As others have pointed out, the flat portion of the shaft for clamping the fan body was not flattened enough on the shaft. I was just making sure the hex bolt was tight on the rounded part of the shaft and has been working fine since installation. It only took 15 minutes to disassemble the old parts and assemble the new motor.