Tropic Marin Precision thermometer for use in fresh and salt water aquariums. The Tropic Marin High Precision Thermometers are individually handmade and calibrated in Germany by experienced craftsmen. If handled and stored properly, their maximum deviation is one fifth of a degree. Scale is from 64 °F (18 °C) to 86 °F (30 °C). The maxiumum deviation is one fifth of a degree.Do you have questions about this article ?