Flare Gun

A flare gun is a tool used to signal someone for help or to start a fire.

TV Series
In Spend, A flare gun is also used by Nicholas when they attempt to retrieve the pieces to fix the power grid in Alexandria.

Flare guns are used by many other Alexandrians trying to draw the quarry herd away in "First Time Again".

Trivia

 * Walkers are temporarily distracted by flares, as they provide bright light and make a hissing noise, but once the flares goes out, they go back to wandering.