Corrosion Inhibitor Plus 1650 is now being replaced with "Molyamor 350" Corrosion Inhibitor by Central Boiler. You will receive this product instead of the Corrosion Inhibitor bottle pictured. Application is the same. 1 gallon treats 200 gal. of water. Recommended for all Central Boilers to neutralize water We cannot ship to P. O. Boxes , AK, or HI UPS ONLY