This premium quality, compact and powerful 3.7 Volt  2,200mAh Battery Stick, Power Pack,USB Recharger was made by GOAL ZERO.  The round silver metal cased battery stick is in Lightly Used condition and works great. This Li-NMC battery stick is designated the 'Switch 8' model because it has 8Wh (watt hours) of power.  It features USBs for input and output at opposite ends as well as charge and battery level indicator lights.  The battery can be charged from a solar panel or via USB in 4 hours.  Once charged it supplies enough power to charge an MP3 player 3x, a Smartphone 2x, E-reader 1x and give your full size Tablet a 25% boost.  The charge time for most smart phones is a low 1 hour.