For a technical user who expects all-around performance and features out of their headlamp but still values a small size and compact package. This user has the need to run the lamp on alkaline batteries if caught away from a power source for a long expedition. Spot 400 Headlamp Features:- Dual-Fuel: Power with three AAA Alkaline cells (included) or the rechargeable BD 1500 Li-ion battery and charger (purchased separately) for maximum flexibility 400 Lumen max output PowerTap(TM) Technology allows instant adjustment between max output and dimmed power Integrated battery meter display shows % of power remaining Settings include proximity and distance modes, dimming, strobe, red LED night-vision and lock mode Brightness Memory allows you to turn the light on and off at a chosen brightness without reverting back to default setting Red night vision has dimming and strobe modes and activates without cycling through the white mode Multifaceted optical efficiency lens technology IPX8: Waterproof-Tested to operate at least 1.1 meters underwater for 30 minutes. If submerged, water may enter the battery compartment and it will still operate; it should be completely dried out after use in wet conditions Digital lock mode feature safeguards against accidental use when stored in a pack or pocket