This is a very unique endpin jack because it requires no internal parts to install or lock in place. One simply drills a 1/2" hole in the endblock of the guitar where the original endpin would go and then you use a 9/16" -12 tap to thread the hole. At that point, using our endpin tool, you merely thread in the jack just like putting in a screw. If the jack should ever loosen, merely insert the tool and snug it down. It's that simple. This jack can be used in mono, stereo, or battery disconnect/switching modes.