Synergy Digital Remote Control Battery, Works with Logitech Harmony 785 Remote Control, (Li-Ion, 3.7V, 950 mAh) Ultra High Capacity Battery - Walmart.com
Harmony 785 Universal remote working better than TiVo's own remote.
Logitech Harmony 720 Infrared Universal Remote Control - Newegg.com
FS: Logitech Harmony 785 with Charging Cradle - Stereo, Home Cinema, Headphones Components - StereoNET International