Tropic Marin ATM50002 Precision Thermometer Tropic marine precision thermometer They are individually handmade and calibrated in Germany by experienced craftsmen If handled and stored properly, their maximum deviation is one fifth of a degree. Tropic marine precision thermometer They are individually handmade and calibrated in Germany by experienced craftsmen If handled and stored properly, their maximum deviation is one fifth of a degree If handled and stored properly, their maximum deviation is one fifth of a degree.