Here at LA County Fire Heavy Equipment Unit, we also use this system in conjuction with our SCBA during Commercial Structure Overhauls or HAZMAT incidents.  It plugs into the SCBA and is used for escape if we encounter any mechanical failures or incidents where we have to dismount the tractor and escape to a safe area.  It allows us to depart the operations area without compromising our airway.
Survive Air 15 Minute Escape Bottle - Used for Fire Dozer Entrapment or Burn Over Incidents