Signal flare

From RedAllianceWiki

A handheld signal device, a simple cardboard tube with a metal cap that fires one or more coloured flares into the air. These flares have been a usual sight in the hands of Soviet and Russian soldiers since the war in Afghanistan. They can be seen sticking out of magazine pouches, pockets or wherever the soldier likes to stick them. These are sometimes cut down after use, and used on the AK-74 family of assault rifles to keep the barrels protected from dirt.

Gallery

A bunch of signal flares.

The bigger, 40mm, illuminating flare.

A standard flare next to a 40mm one.

A Russian soldier, using a cut-down flare to keep the barrel of his AK-74 clean.