A helmet comprising a helmet shell; a breathing apparatus face mask and a visor, for breathing apparatus and the visor being connected to the helmet shell; an augmented reality viewer Positioned within the helmet shell and adapted to receive a video signal and to display the signal as a video image, the video image being arranged such that it can be viewed by a wearer of the helmet; the helmet further comprising a power socket adapted to be connected to an external source of power for the augmented reality viewer.