Summary: need to buy 3m double-sided thick tape with white foam center and use a couple layers to pad the units ride. for example, put 4 layers across the front and 3 across the back of the bottom of the mount if the dash slants forward, to level the unit. The foam absorbs bumps and the levelness keeps gravity out of the picture, and the 3m tape grips forever that way. Worked this way for 5 years, just bought mount 2 to take unit back and forth between a second car. Using Street Pilot III that came with one of these and with the unit harness you need to snap into this mount.