TerraLux TLH-50 LED 540 Lumens Headlamp Runs On: 2xCR123 (included) Output Mode/Runtime: Max: 540 lumens/3 hours - High: 250 lumens/4.5 hours - Medium: 100 lumens/12 hours - Low: 20 lumens/65 hours Water Resist Rating: IPX-7