Something of a niche product for most, but very useful if you need to erect a fence. We recently got a Labrador puppy and SWMBO wanted a stock proof fence putting up around the lawn so we could let it out in the garden and it wouldn't escape.
Normally we would push the posts in using the hydraulic arm on the Loadall. However, big tyre tracks across the lawn would probably have resulted in serious disapproval from my wife. The Poat Driver is basically a big heavy steel tube which you put over the top of the post and wack up and down to drive it in. Best operated by two people. It's better than the traditional big rubber hammer, as you can't miss the top of the post, like you can with a hammer. I am sure that you can get these in your local hire shop if you think you will ever need to use it once.