Synergy Digital Speaker Battery, Works with Logitech S715i Speaker, (Ni-MH, 3.6V, 1500 mAh) Ultra High Capacity, Compatible with Logitech 180AAHC3TMX Battery - Walmart.com
Kastar 1-Pack Battery Replacement for Logitech S715i Rechargeable Speaker with iPhone/iPod Dock S-00100 984-000134 984-000135 984-000142 993-000459 - Walmart.com