A wide variety of mounts use the 17mm ball. Garmin typically has a pressure fit socket that the ball goes in. However, that socket over time can wear out and your Garmin will begin to sag. We've solved that issue by bumping up the ball diameter by .2mm. This creates a tighter hold on the ball and reduces slippage. There is also a small square of 3m 7070 UV Film included that can be used in more aggressive off road applications. You simply place a small square of film on the ball, and it creates an even more secure hold at the ball and socket. The CNC Machined Aluminum will not wear down, and it will not crack at the neck over time with excessive vibration as some of the plastic alternatives are prone to.