Weighing only 15 grams this headlamp accessory light was primarily designed to replace the standard wire clip on your existing headlamp that uses a rear or remote battery pack. Taking this concept a step further Pilot attaches to most headlamps that don't use battery back wires and is perfect for attaching to your backpack and hydration straps. This sytem provides the security of always having a light nearby - Just In Case. Lamp: High Powered LED Batteries: 2 Lithium Coin Cells (Included) Burn Time: 12-14 Hrs. LED Life: 10 000+ Hrs. Weight: 15 grams w/Batteries