THIS AWESOME PRODUCT KEEPS YOUR WEATHERVANE ROD AND DIRECTIONALS FROM SPINNING AROUND AND GIVING YOU THE WRONG WIND DIRECTION.YOU CAN USE THIS IN MANY WAYS WITH YOUR CUPOLA..YOU CAN INSTALL IT ON TOP OR INSIDE OF THE CUPOLA.THE WEATHERVANE ROD WILL PASS THROUGH IT AND YOU CAN ADJUST THE HIEGHT OF THE ROD WITH THE TIGHTENING BOLT.QUESTIONS ?? 1-877-782-8837