Works but mine was defective.
Nice concept/idea. The first time I put this on over my boot I found a tear but it looked like the plastic was melted by something hot or was caught in the blue hard plastic part when it was set shut. I used waterproof first aid tape to close both sides but that didn't help. The seal at the top is pretty good and keeps water from entering. I tested it with the seal facing downwards into the rim and upwards above the rim and it didn't leak water.
Rating: 2 stars