A noise generation device comprising: a housing defining a chamber, the housing comprising a wall member moveable between a sealed position and an open position, wherein in the sealed position the chamber is fluidly sealed and in the open position the chamber is open； an injection assembly for injecting combustible material into the chamber； and a triggering assembly for triggering the combustible material to combust inside the chamber to generate a noise, wherein the noise generation device is configured such that the moveable wall member moves from the sealed position to the open position on combustion of the material inside the chamber to allow material to exit the chamber. A gun attachment and a simulation weapon are also disclosed.
