IPX7 - that's 30 minutes at 1 meter. Only 8 hrs battery life (so 5, really) but possibly a handy plotter for a kayak or Jetski (grrr) or SIB with a BlueChart loaded.
Its a much bigger screen than normal handheld units and It would also be useful on the motorbike and much cheaper than the Zumo they make for bikes .
battery life and the need to recharge is the bigest drawback for an real outdoor GPS . If it had the option of using normal AA bateries then it would be better .