ITEM NAME:2S Li-ion Lithium Battery 18650 Charger Protection Board Module 3A 7.4V 8.4V Gn.Maximum Working Current: 3A. B+ B-: The interface of battery core. Short circuit protection. P+ P-: The connector of battery board. Internal Resistance: Less than 45m ÃŽ ©. B+: Battery V+ Positive. B-: Battery V- Negative.