Here is what I do. I have a standard Garmin GPS. I believe the model is 52LM. They work very well and cheap enough to replace if something happens to it. I pop it off in about 10 seconds if I wash the bike or put a sandwich bag over the top of it if I am caught out in the rain and don't want to do without it. Sometimes I just put it in the trunk if I expect a rainy ride and don't need it. The mount is from Ram Mounts and uses the screws that go into the brake reservoir. The power comes from the left compartment power socket where I have a usb adapter. My setup has been trouble free and an add on I really like to see what roads are coming up soon in front of me. The 7" model would be something I would consider in my current setup.