Durability & Style: Crush proof composite material, dual-injection molding make it one of the most durable and yet stylish external batteries available. In addition, the portable charger can maintain up to 95% of charge after six months in standby (when USB disconnected). A great feature for emergency backup. Unique Charge-Through (a.k.a. pass-through charging) Feature: You can charge Zendure while charging your devices with a single wall charger, a feature rarely seen in other power banks.