Version A has a self propelled unit manufactured by GT. Turn the mower upside down and check to see if your self propelled unit has "General Transmissions" stamped on the surface of the black cover. See diagrams above.

Version B has a self propelled manufacture by EGO Chervon. Self propelled unit is without a black cover. See diagram above.

Version A has a self propelled unit manufactured by GT, main motor is double-insulated, was produced in or before May, 2019 and has a serial number less than NLM08190507851X. Turn the mower upside down and check to see if your self propelled unit has "General Transmissions" stamped on the surface of the black cover.

Version B has a self propelled manufacture by EGO Chervon, main motor is single-insulaated, was produced in or after May, 2019 and has a serial number equal or greater than NLM08190507851X.

The two version of the self propelled unit include the control PCBA and Motor which are not interchangeable between models.