Ethylene glycol
propylene gylcol is Green in colour and is used in a number of applications as it is much less toxic than blue coolant. Although it requires a more specialist tester than standard coolant and cost from £8 upwards
The regular type called(ethylene-gylcol based) or just use the factory coolant call Toyota long life).........
It use to be said a high concentrate of gylcol would eat away at gaskets. Not too sure if this is still the case