ShellZone DEX-COOL 50/50 Extended Life Antifreeze/Coolant is a single-phase, ethylene glycol based, extended life, universal automotive engine coolant based on a unique extended life carboxylate inhibitor system. ShellZone DEX-COOL 50/50 is suitable for a five year or 150,000 mile service life in automotive applications. In heavy-duty applications not requiring nitrite. ShellZone DEX-COOL 50/50 is a 50/50 volume mixture of Shell DEX-COOL with deionized water. Use: Shell DEX-COOL 50/50 is intended for use as an extended life universal automotive gasoline or diesel engine antifreeze/coolant.