You may want to check out the Preon P1 (1 AAA). At 2 lumens it lasts for 23 hours. It has an optical-grade glass lens and can light up the night with 70 lumens if need be. You see them a lot in the medical world. RNs use it mostly on low. The smoothness of the threads, color rendition, and its ability to tail stand are among its claims to fame. You can get a click switch ($7.00) for the back if that's what you're used to.