The low-profile Nav-Mat III weighs in at about 1.3 pounds and doesn't use adhesive to hold its place. While the hefty mat is not the most portable accessory we've tested, it is easy enough to transfer from vehicle to vehicle.
The smooth plastic disk at the top of the mat is generously sized to accept almost any suction-cup-mounted portable navigation device or smartphone cradle. We were even able to get the massive 3-inch Panavise suction cups for our in-car cameras to stick.
If you're a single-car owner and you want the lowest-profile solution, the adhesive Bracketron Nav-Mat II is still my favorite dashboard-mounting solution. However, for people who want a dashboard mount that's easily transferable (multicar families or users of car-sharing services) the Nav-Mat III is a good option.