Amazon.com: Synergy Digital Remote Control Battery,Compatible with Logitech Harmony Touch Remote Control, (li-ion, 3.7V, 1100 mAh) Ultra High Capacity Battery : Health & Household
Logitech Harmony One Remote Battery Replacement - YouTube
Logitech Harmony Ultimate Battery | Logitech Harmony One Battery - New 3.7v 1100mah - Aliexpress