Phoenix Systems (3003-B) Brake Fluid Test Strips, 2 Strips Per Package, Reveals Brake Fluid Condition May save you from paying for an un-needed brake fluid exchange. Gives you the peace of mind that your brake fluid is good and is safely performing its proper function. Identifies potential brake flulid related problems before they occur -thereby ensuring your safety. Simply remove the test strip from the foil wrapper, dip it into your brake fluid and 60 seconds later you will know the condition of your brake fluid. (scientific proof) Great for DOT 3, 4 and 5.1 brake fluid (most vehicles use DOT 3 or 4)