The secondary filter is located behind the grill in the bottom of the bag compartment and acts to protect the motor from dirt particles.
Note - The filter may be green or white in color. Measures 5" x 2 3/16" x 3/8" with a rectangle notch. Should be cleaned with each bag change and replaced every 3 to 6 months.
Fits many WindTunnel Self-Propelled, Tempo and Widepath models.