BaseCamp LED Lanterns utilize state of the art bulb technology and proprietary, advanced reflectors to pierce even the darkest nights. While total rated lumens are important, BaseCamp lanterns deliver "effective light"...defined as the light you need to perform your task. While your eyes can't measure lumens, they sure can tell you if there is enough light to read in the dark or walk in the woods at night.Specifications and Features: Two speed fan with foam blades Energy efficient CREE white LED rated to 50 lumens Carabineer hook included Operates with 4 x D batteries (not included) Up to 48 hours fan run time on low,up to 24 hours on high 100+ hours light run time on low