3400mAh Extended 533-000116 Battery Replacement for Logitech UE MegaBoom S-00147 Wireless Waterproof/Shockproof Bluetooth Speaker - Newegg.com
UE Megaboom Wireless Speaker Review
Synergy Digital Speaker Battery, Works with Logitech UE MegaBoom 2 Speaker, (Li-ion, 3.7V, 3400mAh) Ultra High Capacity, Compatible with Logitech 533-000104, F12431581 Battery - Walmart.com