Synergy Digital Speaker Battery, Works with Logitech UE MegaBoom 2 Speaker, (Li-ion, 3.7V, 2600mAh) Ultra High Capacity, Compatible with Logitech 533-000104, F12431581 Battery - Walmart.com
UE Boom Battery Replacement - YouTube
Cameron Sino Battery for Logitech UE Boom 2 UE Boom 2 Ultimate, fits 00798-601-8207, Li-ion 3.70V 3400mAh / 12.58Wh
3.7V 3200mAh Li-ion Battery for Logitech UE BOOM 2 Bluetooth Speaker Rechargeable Accumulator Replacement 533-000104,533-000138 - AliExpress Consumer Electronics