M18

A smoke grenade is a canister-type grenade used as a signaling device, target or landing zone marking device, or as a screening device for unit movements. If movement (such as flanking maneuvers or retreat) is necessary, smoke grenades can be thrown prior to movement in order to provide a wall of visual distraction that reduces the accuracy of enemy fire and temporarily deceives them as to the force's location. The most common color for concealment smoke is white or grey. With the advent of thermal imaging, which can spot troop movements through smoke screens, the newest smoke compositions now include a "multi-spectrum" component to make them IR impermeable. Smoke grenades can also be used to signal aircraft. Since locating a target from above can be nearly impossible, even with good radio contact, colored smoke grenades are often used to allow aircraft to spot them. Common colors are red, yellow, green and purple, and all use very brightly colored dyes to increase the likelihood of being spotted from above.