My WM Caribou was thouroughly tested the first night I used it, about six years ago. I was on a motorcycle solo trip and slept out in the open. Chance of showers. All over me that night.:) I felt clammy sleeping that night, water was puddled up on the bag the next morning. When I got home, I weighted it again and it still weighted the same. Sold me. It only has the microfiber shell. I can see thru the thread holes now though, so I don't know what is going on, maybe it has been used too much.