Magnetic tank GPS/Cell phone holders?

[Cormanus]

Looks pretty neat. I'd be happier with it on the bar, but that's just me. My LifeProof case is said to be weatherproof. As recommended, I tested it underwater when I bought it and it came up trumps. The only reason I don't work it all from my pocket or a bag is that, on the rare occasions I use the GPS, I want to be able to see it as well as hear it. I'd worry that I wouldn't see it easily in that bag on the tank.