There’s no reason to hoard your battery power when you have the OtterBox OtterSpot Wireless Charging System Stackable Qi Chargers. This system of wireless chargers comes with a charging base and an additional power bank. They’re stackable, so they won’t take up any more space when they’re charging. However, when you need to use both separately, unstack them to place your Qi-enabled devices on top. These stackable wireless chargers might just make you the favorite friend because no one’s phone will die around you again. The stackable power bank base provides 36 watts of power, which is enough to charge your device along with three OtterSpot batteries. Because each additional battery offers 5,000 mAh, you’ll practically be prepared for an entire week away.