Must have if you really want security. Required in some states.

The Nuvi comes with the windshield suction cup mount deal, which is good, if your windshield is fairly flat and clean. With all suction deals, over time with sun and weather, the plastic wears away and the suction just doesn't work. I just bought the Nuvi660 for ($400) good money, so I don't want it crashing down on me.

I felt safer getting the permanent dash mount. The mount can be put on the dash with permanent "3M" type tape (supplied) or a "temporary" tape which is supposedly removable, but then I think it's then not usable again.

Anyway, I have mine mounted with the permanent mount and it's worked great. I actually have the base from my old StreetPilot 2620, which is the same as this base. The base has stayed on for 3 years now with no issues.

When I mount the Nuvi660 on this mount, I feel so much more secure and confident that this GPS is not coming off my dash until I'm ready to remove it. Also, in two States, California and Minnesota, I believe, you can not use the windshield mount, so you have to use a dash mount of some sort. I prefer this over the bean bag because around tight turns the bean bag can still roll.

Excellent product for $26+.