Smoke grenade
From Halopedia, the Halo wiki
Smoke-producing flares are used for a variety of reasons by the UNSC. Different reasons appear to have different colors of smoke attached to them. There are a variety of smoke-producing items, none of which has yet been seen in any Halo video game. But they will possibly make an appearance in Halo 3, because a "smoke bomb" was discovered in Hex.
- Signal Flare: "Smokers" are used to alert allies of a friendly's position. They utilize thick, green smoke.
- Smoke Canister: These are used to signal for pickup after a mission. They create thick, blue smoke. These are also referred to as "smoke grenades."
