This Garmin Xero ARCA Mount is setup to be adjustable left to right so you can move the Garmin itself closer to your rifle or further out. Allowing about 2 inches of travel over all. It also has a centering rail so you don't have to worry about the chronograph being canted off parallel to the barrel. The ARCA clamp is integrated into the mount and it has an ARCA rail for tripod mounting as well. 
The Garmin is secured to the mount with a D Ring screw to allow for easy tension loosening to move it left to right as you move it from rifle to rifle! 
All hardware needed for the mount is included!