No tuning was necessary, as the SWR was 1.2 to 1.4 across the entire 2 meter band right out of the package. I also like that this antenna stays vertical even at highway speeds.
Got 1.04 swr, at 167 but had to use slightly longer bolt in tip and grind head round. Crystal clear 35 mile simplex line of sight contact 10 watt mounted by driver mirror on my pickup.