Nuvi Series, StreetPilot c5XX Series Clipped my Garmin Nuvi 250W to the swan neck mount with ease. The mount sits on top of the dashboard and stays rock solid - no shake or vibration at all. I took the car out for a test drive and did a few sharp turns. The mount did not budge, passing the 'test-drive' with ease. A great bit of kit and well worth the money. No more unsightly tell-tale suction cup marks on the inside of the windscreen. Buy it!