CM012+GN014-SPH+APTTGO520: Deluxe Non-Skid/Friction Style Weighted Dash Mount with Safety Hook for TomTom GO 520 530 720 730 920 930 Edition GPS
I thought this would slide around, but it doesn't.  I have had only one instance where it slid, I was pulling out to the left very fast and it slid.  There is no bouncing from the GPS, I love this since my suction cup won't stick t my windshield when it's cold out.  I live in NH, so it's cold out a lot.