HIGHLAND 500 Gallon SKID TANK Application: Aboveground Type: DOUBLE WALL Material: Mild Carbon Steel Diameter: 4'0" Length: 5'5" 10 Shell 10 Head 10 Outer Shell 10 Outer Head Tank includes: (1) 4" fitting through outer shell only, mark with special warning label-interstitial e-vent use only (1) 4" fitting - primary e-vent use (4) 2" fitting (1) 2" interstitial monitor pipe Primed exterior