Currently planning a full-scale, documented test of the various LED colors of Photons using 2032 cells, everything from white to purple set to run until they bust in a tamper-proof case possibly in a chilled environment to mix things up a bit. If the topic ever comes up again I will keep a chart around of the tested run times using cells from the same pack. From there, field testing of the long-runners to figure out what is usable and what isn't. I'm sure red will triumph, but red lights by nature are so dim the military trusted them not to be noticed from a distance. I'm looking for longest running color that can actually be used.