Review on Stay Visible and Dry with the BTR Waterproof High Vis Reflective Backpack Cover by John May

I just went out in the rain with this pack: it keeps my pack very dry in every way [including the bottom]. Cons [minor for me]: Instead, my buttocks were wet as the water slid through the outside and into the top of my butt. I have the yellow version for better visibility when cycling in the dark before sunrise and after sunset. Regarding the fit: I have the large size [22.5 x 18.5 inches] and it wrapped around my backpack very well and tightly. The type of backpack I have is a black High Sierra measuring 20 x 13.5 x 8.5 inches. Another benefit: Riders can easily see me from over 500 feet away and give me wide bike space afterwards. Verdict: It fits in my pack well, it keeps my pack dry, and it provides good visibility from at least 500 feet.