Tinytag Plus Radio Temperature Data Logger for Four External Thermistor Probe. Measurement Range: -40 to +125°C, Resolution 0.02°C. or better. Logging Interval: 2 mins to 10 day with 2 Fully Programmable, Latching Alarms, per Channel with 1 sec to 10 days Alarm Delay. Red LED and Tinytag Explorer Connect Warnings with Email and SMS options. Reading are transmitter immediately, but Off-line Memory 2 Weeks @ 10 min logging. EU Radio frequency 869.88Mhz, power <5mW. Range up to 200m line of sight. IP67 Enclosure. Operating Temperature -20 to +55°C. Units are supplied with 2 x 1.5V Duracell Industrial ID1400 C Type Alkaline Batteries suitable 12 months operation.