OM-91 is an OM-90 series temperature datalogger. The OM-90 Series is a portable, compact portable USB temperature data logger. Temperature is measured to an accuracy of ±0.3°C over the range of 5 to 60°C (41 to 140°F) and ±2.0°C over the full range of -30 to 80°C (-22 to 176°F) and temperature is logged at a user configurable logging rate which is software selectable. Ideal for transportation applications where it is necessary to document that the material in-transit has stayed within particular environmental limits.