Zerex original (the "green stuff") full strength (part ZX001) and, to a lesser degree, their 50% ready to use (part ZXRu1) antifreeze in 1 gallon containers is available at NAPA stores nationally. Unfortunately it is often a special order product not always in stock in a given store's inventory. I am advised by the manufacturer's parent company, Valvoline, that it is also available at Pep Boys auto parts, although the stores I visited did not carry it. I have had a difficult time finding this product in New Jersey. Unfortunately it cannot be shipped to retail customers due to it's haz-mat classification. Most R&S Strauss stores in my region carry Zerex G-05 (the yellow stuff) and Zerex Dex-Cool (the orange stuff), both in diluted 50% versions. Don't be confused, as these chemistries ARE NOT equivalent to Zerex original. I cannot/will not use them in my older GM automobiles. If you are stuck and cannot locate the Zerex original formula, I would opt for a reasonable substitute such as GM's Antifreeze coolant available in full strength 1 gallon containers. This is available at your local GM dealer's parts dept and has the following part numbers: OLD GM PART

1052753, A/C DELCO PART # 12378373 (outside of USA), and

GOODWRENCH / NEW GM PART #12378560. Please post an update if you find a source to purchase ZEREX Original.