Just a short note on my personal experiences with the light sticks in cold weather. Since they are dependent upon a chemical reaction, the colder the temps. the less they glow. It has been mentioned in various places, to get some additional time out of the sticks, put them in the freezer after a few hours of use and you can usually slow the reaction down enough to use them the next night. This same phenomenon, will also affect their usefulness outdoors in very cold conditions. We often train at night in adverse conditions. We had an adverse weather training drill in Altoona, PA when it was around 0 degrees F, with freezing rain, close to two feet of accumulated snow and 20+ mile an hour winds. We tried to use the light sticks to mark key areas and pieces of equipment, they were so dim, they were useless. After the drill as soon as we got them into a warm environment they glowed brightly. Pete