A composition which retards the spread of fire, protects assets at risk from fire damage and emits a material which aids in extinguishing the fire. In the first embodiment of this invention, a resistance heating element is provided which includes a resistance heating material and an electrically insulating, substantially water impervious sheath disposed over the resistance heating material to form an active element portion having an envelope of about 50 in3, a total wattage of at least 1000 W, and a watt density of no greater than 60 Win2. In one embodiment, the imaging beams are deflected in a slow scan direction to compensate for the spiral advance. These various reflecting points are aligned to indicate proper alignment of a trailer to a vehicle.