The Rhino Duo-Chek Engine Coolant and Battery Test Refractometer, Nos. DC60 and DC70, from Reichert offers an accurate, fast and easy-to-use method for testing engine coolant freeze point, glycol concentration and battery charge condition. Water-resistant and dustproof, the refractometers make sure internal optics cannot be contaminated. The device is shock-resistant and drop-tested to 3'. This all-in-one tool includes six measurement scales. No batteries required.