This mount has a lot of neat features found in other cup holder mounts.  First, it has a flexible shaft that will attach to the back of the GPS.  The mount swivels and pivots after mounting.  It features an adjustable flywheel base that expands to fit varying cup holder opening (up to 3.5 inches wide) except for those that are so large that the 7-Eleven Big Gulp falls over.

Fits the socket on the back of the GPS (or cradle for the GO series)

Fits many TomTom Models including:
Via models:  1535, 1535T, 1535M, 1535TM, 1505, 1505T, 1505M, 1505TM, 1435, 1435T, 1435M, 1435TM, 1405, 1405T, 1405M, 1405TM, 220, 180, 160, 125, 120, 110
GO Models:  Go 950, 940, 750, 740, 550, 540 Live & Traffic
GO Models:  2505 TM, 2535 M, 2535 TM, 2535 TM WTE, Live 1005