I took my suit for a test dive in Troy Spring this weekend. My p-valve appears to not leak, but I've got a leak elsewhere. I believe I have the neck seal worn improperly. It's a neoprene seal with a smooth side on the outside and a cloth side inside. I have a feeling that it needs to be rolled inward in order to make a seal against the skin. It's never been trimmed and it's not exactly tight - I have a 17"+ neck.