Bull Dog Pipe Mount Jacks are a great way to weld your jack at your desired location and still be able to swivel the jack to stow it away while towing. These Jacks can be welded to your trailers tongue or frame material. If you are just replacing your existing jack, in most cases you will just simple mount the jack to your existing welded on mount. This system allows you to also swivel your trailer jack to store it parallel to your trailer tongue. Additionally, these jacks are very common as back supportive jacks for utility trailers and equipment trailers. They will mount to the back of the trailer to support and its wait while sitting idle.