The RAM mounting system is a great way to unlock the potential of your Garmin GPS. The only problem is that Garmin uses a different sized ball fitting. That's where this 17mm Garmin ball to 25mm Ball (RAM call this B-Size) adapter comes in.
The 17mm Garmin ball clips into most Garmin portable navigation device mounts, and the 25mm ball allows you to use any of the RAM mount B-size mounting system parts for more secure mounting options.
