Type of battery: Lithium-ion. Voltage: 12V. This battery pack contains 3 pieces of 3.7V 18650-2000mAh Lithium-ion batteries. Only weighs 0.4 lbs Compatible with WORKPRO 12V: Well compatible with WORKPRO 12V Cordless Power Tools such as drill, reciprocating saw for W004548A//W125042A/W125045A and more) Much Safer: Safeguard features against incorrect voltage, battery overload, short circuit, internal overheating. No memory effect, can be charged freely Environmental-friendly: Innocuous to the environment. All 3 pieces lithium-ion batteries in the battery pack accord with certification requirements of CE/GS/EMC/PAHS/ROHS One hour to Charge: When used with the WORKPRO 12V Fast Charger WORKPRO 12V 2.0Ah Li-ion Battery Packs