A Cluster Launcher is required to use a Large Blue Rocket Cluster. (see Notes section)
Large Blue Rocket Clusters are crafted by engineers with a skill of 275.
(Unlike several of the Lunar Festival fireworks, this item can only be crafted by Engineers.)
Unlike many fireworks in WoW, Lunar Festival Rocket Clusters (any size, any color) require the presence of a Cluster Launcher object on the ground in order to use the firework. These are widely available during the Lunar Festival only; near Lunar Festival revelers in cities and in Moonglade, and at other odd locations (there's some at the fishing dock in Orgrimmar). You can also spawn your own Cluster Launcher for 30 minutes by using a , made by an engineer from schematics purchased from in Moonglade during the Lunar Festival. The schematics cost 5 . The Cluster Launcher item does not bind; it has only one charge and is used, not equipped, so it is Consume on Use.