Artillery Smoke Grenade (Fallout 4)

The artillery smoke grenade is a weapon

Gameplay
These explosives are used to mark high-priority targets for artillery support. They can only be used outside and within range of a workshop settlement that contains a manned artillery piece. If these conditions are met, the area marked by an artillery smoke grenade is bombarded with powerful explosives. Each artillery piece the Sole Survivor has built and manned will send five additional shots, provided that they are also within range. The grenade produces blue smoke.

Locations

 * The Sole Survivor acquires the artillery smoke grenade during the Minutemen quest Old Guns.
 * After the initial Old Guns quest, the yellow ammo box in the armory will continuously spawn 10 smoke grenades, along with a variable number of flares. It is not required to leave the cell, simply leave the armory and return to collect more each time.
 * The workshop at Sanctuary Hills, or any other settlement where one has built artillery and assigned someone to it, will periodically be restocked with ten smoke grenades.

Behind the scenes
Written on the side of the flare it says 'Piece of Flare' which is a reference to the 1999 film Office Space.