Extech RF40 Battery Acid and Engine Coolant Refractometer Fahrenheit
The RF40 measures the freeze point of automotive coolants (propylene glycol and ethylene glycol) from 32°F to -60°F. It also indicates the specific gravity of battery acid and provides a quick reference of battery charge condition. It only requires a sample of 2 or 3 drops for fast and accurate readings. Automatic Temperature Compensation provides repeatable results. Comes complete with storage case and a screwdriver and vial of distilled water used for calibration.