DayZ field wiki · Survive
Chemlights
A quiet lamp
Short answer
Throw one in a room. Mark a meet. Not a flare over the town.
Also: glow stick · chem light
How it works
Chemlights glow. They are a tell if you wear them on a helmet inland. Useful on the floor.
What to do
Throw, loot, leave.
Don't
Don't necklace them for a festival in Stary.