18650 battery 4.2V vs 3.7V - comparison guide for 18650 with different voltages-Tycorun Batteries
Versatile 18650 Li Ion 3.7 V Rechargeable Battery For Electronics, Clock, LED, Rechargeable Lamp, Bright Flashlight, And More 4900mAh, 3.7V/4.2V From Epochcom, $2.95 | DHgate.Com
WLW Li-ion 18650 5800mAh 4.2V battery pack With 2 Pin Connector – Little Tokyo SA