4 ultrabright Nichia 5 mm LED's, 30% brighter than standard LED's. Current regulated for constant output. 4 output modes-hi, med, low and safety flash. Low battery indicator light. Waterproof to 1 meter for harsh conditions. Illuminates up to 37 m away. Power: 45 Lumens (3AAA). Burn time: 1 hour (high), 10 hours (medium), 31 hours (low). Weight: 3.4 oz.