The electronically regulated LED utilizes a Total Internal Reflection (TIR) lens to maximize light transmission and create a beam with a bright center and gradually diminishing corona. The one-battery E1L has a maximum output of 30 lumens and a total runtime of 10 hours. The two-battery E2L has a max output of 45 lumens and 14 hours of total useful light: Surefire; E1L $99, E2L $129; (800) 828-8809; www.surefire.com