The Bergen Pannier 2 is the best commuter pannier bag. It is a waterproof pannier that securely fastens to your bike's rear rack with super-strong FidlockA(R) magnetic buckles holding up to 25lbs. Once you reach your destination, this bag easily transitions to a stylish crossbody bag. The Bergen has coated zippers and a built-in rain cover for heavy downpours, plus an exterior water bottle pocket.