Synergy Digital Speaker Battery, Works with Logitech UE Kora Boom Speaker, (Li-ion, 3.7V, 2600mAh) Ultra High Capacity, Compatible with Logitech 533-000104, F12431581 Battery - Walmart.com
Amazon.com: Battery Replacement for LOGITECH UE Boom S-0012 533-000105 NTA3083 : Health & Household
UE Boom 2 review: Top Bluetooth speaker gets improved sound, full waterproofing - CNET