Easily and securely attaches to Echo Dot by a magnet with no interference. Easy to separate. 5200mah LG battery cell Enables your echo dot to continuously function for more than 6 hours without being plugged in. Recharges using the Echo Dot power adapter. Intelligent battery management system allows the user to leave the power adapter plugged in without damaging the battery. Please use the plug and cable that came with the Echo Dot.