Quantity in each package: 1Plug-In Transient, Surge, Lightning, & Spike Protection for ECM Motors. To use, simply plug VZPRO directly into motor, then plug motor's harness into the VZPRO... (Full instructions with photos in package.)"The most common cause of ECM Motor failure is damage to the electronics module as a result of poorly conditioned voltage."This unit works with either 120v or 240v GE ECM motors.