Amerex 469 – 125 LBS Purple K, Dry Powder Fire Extinguisher Regulated Pressure 16in Wheels, These 110 ft3 nitrogen cylinder operated models feature a pressure regulator and two-wheel options. The older, traditional design allows for adequate pressure to assure a smooth, complete discharge of the dry chemical with pressure reserve for blowing down the discharge hose. Choose either the 16″ semi-pneumatic rubber tire or 36″ X 2½” steel wheels according to the area to be protected. Easy to transport and operate by one person.