Bought this to go on my motorbike. It sits behind a screen so does not get any excess spray. I read that it may not be completely watertight on another review, so thought of a little experiment. I filled the case with paper towels and attached it to my motorbike. i drove for 20-30 minutes in the rain and on my return home, I opened the case to see if any of the paper was wet.
This case is as watertight as a colander!
I never expected it to be 100% dry inside, but the whole of the inside was soaked. If you are going to put your precious sat-nav inside stick it inside a freezer bag or similar or you'll be risking it's life.
To call this waterproof is completely mis-representation as it is clearly not.
That said, it is a doddle to fit to your handlebars, comes with eay on & off clip and has padded inserts to hold whatever you put inside it.
If used in the dry, I would say this is a handy bit of kit, but avoid for wet weather use as it fails badly