Great Cover, a little pricey, but Very Nice
Installed on my 2015 Silverado 1500 short bed in about 2 hours by myself. I haven't installed the drain tubes yet, but the only areas in the bed that got wet were right under the drain holes and not that much either. I'd say it's pretty weather proof. The lock is nice as well as the keyless open option. Install the side rails and the top with the tail gate closed to make sure you don't have a gap between the top and the tail gate.
Please make sure you do your research for the right cover. I spent over a year looking at all the covers I wanted. I finally decided for this one and I could not be happier. It looks awesome on my 2010 Chevy Silverado 1500. I have received many compliments about it. My gas mileage has increase as well having it on. I had to add some extra weather strips on back side of the tool box, but overall, I have a little water leak. Mostly everything stays dry.