RAM 2" x 1.7" Base with AMPs and 1" Ball for the Garmin zumo, TomTom Rider & Urban Rider 
The RAM-B-347U base consists of a 1" diameter rubber ball connected at right angles to a 2" x 1.7" square base. The base has four pre-drilled holes at each corner, making the universal 1.5 x 1.188 (hole spacing) AMPS hole pattern.
This adapter/base is designed to hold the following devices:
-  Garmin zumo 400
 
-  Garmin zumo 450
 
-  Garmin zumo 500
 
-  Garmin zumo 550
 
-  Garmin zumo 660
 
-  TomTom Rider 2
 
-  TomTom Urban Rider
Material:Powder Coated Marine Grade Aluminum 
Ball Size: 1" Rubber Ball "B" Size