2100mAh 3.8V Li-ion Polymer Battery Fit for Logitech UE Ultimate Ear Wonderboom Wireless Speaker - Newegg.com
Amazon.com: Synergy Digital Baby Monitor Battery, Compatible with V-tech 5" Digital Video Baby Monitor, (Li-ion, 3.8V, 2100mAh) Ultra High Capacity, Replacement for V-tech BP1763 Battery : Baby
Battery Detector with Polymer Lithium Ion 5100mAh 3.8V | Seeed Studio Wiki