Remember, for best effect, they should be mounted in the curve on a fender/quarter panel, etc. so a beautiful distinct oval is visible. Ideally, the antenna should be invisible in it's fully retracted position (to avoid vandals bending it) but for the "cruise" position 1 to 2 inches sticking out above the panel is most excellent. Always remember, if you have 2 antennae the should have separate controls so they can staggered in height for best visual effect. I've always used manual antennae because I'm a lo-bucker.