Save money on coolants by controlling concentrationBenefits Prevents wasted coolant and extends tool life. Applications Refractometers provide a quick and accurate way of controlling coolant concentration.All you do is put a couple of drops on the prism and look into the eyepiece for the reading. Features Only 2 or 3 drops needed for test.Accurate, easy to operate with simple to read scales.The prism and lens with a simple focus adjustment provide repeatable results. Technical Data ATC (Automatic Temperature Compensation)Models with ATC relieve the user of the responsibility to measure temperature and apply a correction factor when taking readings, automatically. Using 68°F (20°C) as a reference, readings are automatically adjusted to compensate for temperature variance between 50°F to 86°F (10°C to 30°C).EXTECH Coolant Style Refractometer