That smaller black cover you see forms a seal over the battery, the SD card, and the SIM card, to protect them from water damage. You must reseal that cover to make sure the phone's more fragile components stay dry.
The Vortex is water-resistant up to one meter for 30 minutes. That means it will hold up just fine in rain showers, and regular showers, but you shouldn't take it swimming with you.
It’s about half an inch thick, so if you slide it into a back pocket and try to sit on it, you’ll feel it. At more than 5 inches tall, it'll stick out of most pants pockets.
