Whether you call them post-on-pipe or post-n-pipe, the concept is the same. Drill the center of a post and insert a 1 5/8 SDH 40-galvanized pipe. The intent is to set the base of the wooden section of the post 2 or 3 inches above the soil, preventing the post from premature rot and deterioration. This is becoming a common type of fence post in the American Northwest. The post can be lifted off the pipe for replacement and maintenance. Here’s a reputable fence company in Washington State that installs them regularly.

Check out Gibson Fence and Deck for more detailed images and use cases.