[3] A typical design consists of a sheet steel cylinder with four emission holes on top and one on the bottom to allow smoke release when the grenade is ignited.
For this reason, they are favored for use in onboard grenade launching attachments on armored vehicles, which require extremely fast concealment in the event they are targeted by anti-armor weaponry and need to rapidly retreat.
Since locating a target from above (especially in thick forest canopy) can be nearly impossible, even with good radio contact, colored smoke grenades are often used to allow aircraft to spot them.
Colored signaling smoke grenades [4] are widely used in CASEVAC and close air support situations where quickly locating friendly ground forces is of paramount importance.
However, the smoke grenade class is restricted to signaling and concealment under the law of war, and thus they are not considered weapons; since the vast majority are non-explosive, they remain legal for civilian use and ownership in most countries.