We had an interesting install due to an existing pole that that was not 3" and had a concrete footing sticking out of the ground about 8 inches. Luckily, the footing was tapered and after altering this and getting a 3" post that we cut to the height we needed, it works great. It was the only solution that didn't involve completely ripping out the concrete footing and installing a new one. 

If you have a regular 3" light pole and you are trying to spruce it up, then this will just slide over what you have and will be super quick and easy to install.  

Pros: Easy install, durable