I wonder if someone can recommend a product.
Looking for a pocket to go on the shoulder strap of a backpack. Should be big enough to hold a wallet and a phone; keep contents dry in the heaviest rain; secure when you're in a tuck with the pocket almost horizontal; open/close conveniently, velcro flap better than zipper and zipper better than buckle.
The "cellphone pouches" sold by some messenger bag companies (Chrome, Timbukt2, Ortlieb) are sized to hold just a phone and some are not rainproof. I've found a couple of backpacking shoulder strap pouches (Granite Gear, Geek Pocket) that are better, but they either zip closed (slow to access) or are open to above (why?).