Purple Smoke Flare

The Purple Smoke Flare item is a pyrotechnic device used primarily to mark a location by placing a purple smoke column object on the terrain.

Some uses that people have come up with:
 * marking locations for raids
 * smoke bomb the Flag Rooms in the Warsong Gulch battleground
 * props for floor shows and fashion shows

Source
Purple Smoke Flares are crafted by Engineers with a skill level of 335.

The is a world drop, making it much rarer than the and the. Thus the Purple Smoke Flare is rarer than the and the , because fewer engineers have the recipe, and unlike the other smoke flares, the Purple Smoke Flare cannot be purchased from a vendor. The Purple Smoke Flare schematic does not bind, and can be bought and sold at the Auction House.

The Purple Smoke Flare item does not bind, and can be also bought and sold at the Auction House.