Our radiator coolant tester tests hot or cold ethylene glycol-based coolant, including Dex-Cool. This glycol test kit features easy-to-read discs that are magnified by the convex design of the clear thermal resistant plastic barrel. There are six discs. The first five discs show the freezing point of your antifreeze, and the six disc floats if your antifreeze and water levels are incorrect, resulting in overprotection. The ideal reading is five floating discs, which is a freeze indicator reading of -34F or -37C. You may not be scheduled for your next coolant flush anytime soon, but testing your antifreeze is an important way to ensure it is providing proper protection. The clear body of our coolant test makes it easy to examine your anti freeze for impurities, rust, and debris, which can indicate you need to move up your next engine coolant flush. Our coolant test kit is designed to be simple, easy to read, and super useful. If you're serious about protecting your engine, this simple yet powerful tool is a must-have addition to your toolbox.