1,High Capacity Battery Pack BP28 2,Capacity:4400mAh 3,Output Voltage:3. ... ,Weight:128g 5,2*18650 Rechargeable Li-io Model: High Capacity Battery Pack FEREI | BP28 Specifications of BP28:Size: 87.2mm ... 7 to 4.2V Features of BP28:* Professional lithium battery power pack , used for Bicycle Lamp B3/B5/B9 or Headlamp ... Jack and OD5.0mm cable .* 2x18650 Li-ion battery inserted with protection circuit board.