Battery and antifreeze testers are hand held refractometers designed for the indication of specific gravity, freezing point temperature, and battery charging levels. The test requires one or two drops of sample on prism surface to read propylene glycol (-60 to +32°F), ethylene glycol (-84 to +32°F), or battery fluid (1.100 to 1.400 SG). Battery fluid scale also shows conditions such as recharge, fair, and good. It includes adjustable knob for calibration and rubber eyepiece guard.