Here is the wiring kit I used to hardwire my Garmin 3597 to my bike. Check the plug type. Sure, in bright sunshine the screen can be a little hard to read, but that's not the norm. I also purchased a clip-on hood for it that helped...for a while...until one day it blew off on the highway

With a small amount of work I also made my Garmin water resistant and haven't had any trouble with it yet in rain. And if I do...no biggie...these things are very cheap now. I just don't feel comfortable shelling out the big bucks for a Zumo. It's not worth it for my budget.