Slim Charger is a design that took over 12 months to come to life. The problem, a Slim, go anywhere charging device that ALSO provided the power needed. Most other ultra slim charging banks can not provide the juice needed for meaningful charging – they only add 10-20% before losing power. Slim Charger’s design keeps the Slim design while packing an incredible 4000 mAh of power. That means enough power to fully charge you device or share between several devices when on the go.