This RAM high strength composite holder is designed for the following devices: Garmin StreetPilot c310 Garmin StreetPilot c320 Garmin StreetPilot c330 Garmin StreetPilot c340 The holder does not block the internal antenna or speaker and allows for use of the factory 12V power adaptor. Utilizing a 1" rubber ball, this holder seamlessly integrates into any of the RAM compatible mounts. This mount does not include the power adaptor but will accept the Garmin factory power adaptor from the original mounting system. The ball is included with the purchase of this holder. Material: High Strength Composite Ball Size: 1" Rubber Ball "B" Size Colour: Black