A personal powered air respirator, for example a welding or spraying helmet (10), includes a remote controller (30) for adjusting one or more operating parameters of the helmet and a means of displaying information regarding said parameter in, on or adjacent the interior of the vision panel (12) of the helmet. The invention allows for convenient adjustment in use. The remote controller is adapted to clothing, such as belt, glove or pocket, or may be incorporated in equipment for use with the helmet.