Stash this in your pack to provide almost 18 hours of burn time for your HL40II headlamp on maximum brightness!

* Professional lithium battery power pack for Ferei Headlamp HL40II
* 5.5 DC Jack and OD 3.5mm cable with weatherproof connections
* 4 x 18650 Li-ion battery inserted with protection circuit board
* Weight: 235g
* Capacity: 10400mAh
* Output Voltage: 3.7 to 4.2V

**Please note - to connect this battery pack to your HL40II Headlamp you will also need the  - please order this with your battery.