... 18650. Li-ion rechargeable battery packs Model :3.7v 4000mah within PCM protection +wire welcome OEM Key words18650 li ion ... battery pack 3.7v 4000mAh 1 Type: lithium ion battery 2 Volt: 3.7V ... 3 Capacity: 4000mAh 4 CE/UL/RoHs approved18650 li-ion battery pack 3 ... tool, flashlight, torch etc… rechargeable li-ion 3.7v 4000mah battery