GC™ API Registered DEF is manufactured with 32.5% high-purity synthetic urea and 67.5% deionized water designed for use in passenger vehicles, trucks, and construction & agricultural equipment. It is compatible with all Tier 4 final compliant equipment using Selective Catalytic Reduction (SCR) technology. GC™ DEF prevents SCR breakdown, reduces harmful nitrogen oxide emissions by up to 90% and improves fuel efficiency by up to 8%. It is a simple-to-use, low cost, clean solution for meeting 2010 EPA Clean Air Act requirements.

Purity of diesel exhaust fluid is important to maintaining a functioning SCR system. Any chemical impurity in DEF can lead to failure of an SCR system, making it very important to use only DEF products meeting ISO 22241-1 standards. GC™ DEF-32.5 is a stable, colorless, nonflammable, nontoxic fluid that conforms to the ISO-22241-1 specification.