T4216 is one high grade gear oil additive package. This grade package reaches the requirement of API GL-5/GL-4/GL-3 grade gear oil and heavy duty industry gear oil as well. With 4.2% dosage GL-5 gear oil have past CRCL-42, CRCL-37, CRCL-33, CRCL-60 bench test, match USS-224, AMGA250.04 requirement.