*Unique worm-drive damper (A worm drive is a gear arrangement in which a worm(which is a gear in the form of a screw) meshes with a worm gear (which is similar in appearance to a spur gear). The two elements are also called the worm screw and wormwheel.
*Center knob opens and closes the vent wings. In fully open position the vent wings are completely retracted allowing 100% unrestricted air flow.
*360 rotation
*Easy installation and long term durability.
*Accepts 4" flex duct.
Approximate size:
Grille face diameter 5 1/2"
Back diameter 4"
Side: 2"
Please let me know if you have any questions.
Thank you,
Babette