Our goal was simple: design a powerful battery that stacks up - literally. Slimmer and stronger. At (0.39in), Anker"s Astro Slim2 comes with enough power for 2-3 charges on most smartphones in a compact, easy-to-grip case. Sized especially to stack behind your 4.3in smartphone for uninterrupted phone-use while charging. An LED column lets you know just how much juice is left without diverting attention from your work. Say goodbye to knots. Who doesn"t hate tangled cables? With an intuitively-sized micro USB cord for Android, the Slim2 allows you to carry your power all-in-one. Using an iPhone? Plug into the USB port and charge up via your OEM cable. No expense to speed. What"s better than a high-capacity battery that slides into your pocket on-the-go? One capable of simultaneous, full-speed charges. Both ports supply 1A of power with complete safety to your phones, so you can power up in no time and make the most of your day. For optimal use. • For simultaneous, max-speed charging of your Astro and other devices, check out Anker"s new 25W 5-port wall charger or dual-port 24W car charger. • The built-in Micro-USB cord may not work with thicker bumpers or cases.The included Micro USB cable is compatible with the Samsung Galaxy S5, Note 3 and other Micro USB 3.0 devices. To connect, insert the cable"s Micro USB tip into the larger of the two connection ports on your device. • To ensure complete safety and best performance, we strongly recommend using your device"s original cable, a third-party certified cable (such as MFI) or our included cable. Get to know us. The Anker Astro external battery has been voted #1 in class by thousands of online reviewers, while our renowned customer service has made us a fan-favorite across the web.