RED HEAVY DUTY EXTENDED LIFE is an advanced OAT (Organic Acid Technology) “NAPS- Free” Extended Life Coolant Antifreeze that protects against damaging rust and corrosion. NAPS Free (a Nitrate/Nitrite, Amine, Phosphate, Silicate) chemistry ensures trouble free service and does not require Supplemental Coolant Additive (SCA). QC COOL RED Heavy Duty Extended Life is compatible for top-off and service with other modern OAT and nitrated organic acid technology (NOAT) formulations.