Hydrofarm  AELC Active Eye Green LED Cap Light
This green LED caplight clips to the underside brim of most caps. 6 High intensity LED bulbs for extended viewing range. Easy to use thumb switch operation, hands free illumination, 4 different settings, lightweights and compact. 100,000+ hours of burn time. Uses 2 lithium cell batteries, included. 1-Year warranty. This product weighs 0.1-pound. Measures 6-1/2-inch length by 5-inch width by 1-inch height.