only really 2 diffrent types of antifreeze.. ethlane glycol and polypropolene glycol.. polypropolene glycol is enviromentally friendly and is what GM's new stuff is.. Prestone sells it under the name pet friendly ( Ethlane glycol will kill animals if they drink it, and they do all the time )... ethlane glycol, the old green stuff is cheaper, lasts a long time., and orange Dexcool is also ethlane glycol.. you could mix the 2 if you wanted.