The RAM-B-166-G1, twist lock suction cup mount consists of a 3.25″ suction cup locking base, socket system and 2.5″ round base for connecting to the Garmin factory GPSMAP and StreetPilot cradle. The mount is designed with a RAM 1″ diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm; this allowing for almost infinite adjustment and perfect viewing angles. Simply attach the suction cup base to the windshield of your vehicle for an easy and safe way to view your handheld device in your vehicle. High quality materials ensure your electronic device is safe, secure, and within easy reach. RAM’s patented design also dampens shock and vibration helping to extend the life of your mobile device. This mount is designed to hold the following devices: StreetPilot III StreetPilot III Deluxe GPS 75 GPS 50 GPSMAP 172 Series GPSMAP 175 GPSMAP 176 GPSMAP 178C Series GPSMAP 195 GPSMAP 295 GPSMAP 196 GPSMAP 276C GPSMAP 296 FishFinder 120 Series FishFinder 250 Series FishFinder 250C SeriesMaterial: Powder Coated Marine Grade Aluminum Ball Size: 1″ Rubber Ball „B” Size Note: Part number reflects product packaged in clear clam shell for store shelf display. Related Links:RAM GPS Mounts PageRAM Suction Cup Mounts Page RAM® double socket arms with their distinctive hour-glass shape are designed and recognized to provide the best possible performance for most any application.