The Tramming Arm Pro allows you to attach a dial indicator to your Tramming Arm giving you quantifiable feedback.
Your package would include (2) 3d printed pieces, (2) screws, and a dowel pin. Note the dial indicator is sold separately.
Attach the Extension to the Body and use one of the screws to lock it in place.
Secure the Dowel Pin in the hole on the opposite side.
Slip the gauge in the top of the extension arm, and secure it in place with the other screw.
Place in your spindle or router, and do not turn it on, but lower it to the waste board and rotate it manually observing changes from front to back, and left to right, Isolating one axis at a time.