What a great mount! Unlike many other solutions that use universal cradles, this is manufactured specifically for your TomTom One. This fits the groove on the back of the TomTom just like the one that came in the box. That means no cradle is needed.
The popular Cup Holder Mount is about 5" tall. 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.