L Shape Mount for the front or sides of the Ultra, Pro Pack or Universal install. Recommend L Mount for both Vexilar or Garmin(leave note if for Garmin as longer mounting bolt and nut will be required) For Garmin L Mount can be bolted to Handle by drilling 1/4" hole at the height desired.Head mount allows you to mount your arm off the head unit(Longer head screws may be needed.Vexilar Ultra Pack Mount allows you to use the front threaded option and yet the arm can still fold up so you can put your setup in a 5 gallon pale.