SECURITY ALARM

A security alarm for a vehicle, the security alarm includes a housing having, an inner casing having an aperture extending between interior and exterior surfaces, an outer casing arranged to be secured to the inner casing so that an interior surface of the exterior casing overlies the inner casing exterior surface with the exterior casing covering the aperture, the inner casing exterior surface and the outer casing interior surface defining a spatial volume communicating between the aperture and the inner casing exterior surface and the outer casing interior surface, separated between 1 mm and 5 mm, a base configured to attach the housing to a surface, and a motion sensing component including an audio element and being located within an interior space of the housing so that each audio element is located adjacent an aperture of the casing, the motion sensing component configured to detect movement of the housing and generate an alarm signal.