The magnetically-coupled actuator system along with a testing tool allows for primary functionality testing of the Defender OPV at grade level through the overfilll installation tee, without having to remove the entire assembly from the riser.
The remote testing tool will actuate the flapper when inserted down the drop tube and slid by the actuator - this is confirmed visually through a window in the tool.
To accommodate varying tank sizes, the testing tool handle is segmented into six sections for customization up to 11 feet (3.35 meters) in length.