Chem lights are old tech. They suck. With good compact LED flashlights and lithium batteries, really no need for them anymore for most general lighting uses. They have a relatively short shelf life and and brighter ones expire in as little as 18 months, and then must be disposed of, performance drops way, way down in cold temps, are really, rally messy if leak, stains are permanent, must be kept from being exposed to air in their special packaging and if it is punctured, they are toast. High pressure packing often bursts the packing or the tube., so they must be kept in a hard case inside such packing, no off switch, 360 degree light requires special holder for directional use, even then they put out only modest amounts of light not focused at all... I could go on and on. All around a tech that was great in its time, now irrelevant for general lighting uses. In those rare instances where chem light type lighting would be useful, one of the Krill or LED versions are much better. They last longer, are more reliable and can be switched on and off as required.