Testo plastic wireless temperature probe with external probe connection and internal NTC sensor, plus door contact input. 2.4 GHz frequency. In the event of a transmission interruption data is saved in the probes' memory. Measuring range: -22 to 122 degree F. Accuracy: +/-0.7 degree F (-13 to 122 degree F), +/-1.4 degree F (remaining range). Resolution: 0.1 degree C / degree F. Measuring range (Instrument): -58 to 302 degree F. Accuracy (Instrument): +/-0.4 degree F (-13 to 158 degree F), +/-0.7 degree F (remaining range). Resolution (Instrument): 0.1 degree F/ degree C. Connection: NTC via mini-DIN socket, door contact connection cable included in delivery (5.9'). Battery life (Type: 4 AA batteries): Battery life at 77 degree F, 3 years; for freezer applications, 3 years with L91 Photo lithium Energizer batteries). Protection class: IP68. Measuring rate: Standard 15 min, 1 min to 24 h can be set. Conformity with standards: DIN EN 12830. Operating temperature: -31 to 122 degree F. Storage temperature: -40 to 122 degree F (-40 to 50 degree F). Transmission distance: approximate 984.3' free field at a frequency of 868 MHz, approximate 328.1' free field at a frequency of 2.4 GHz. Included wall bracket. Measures 3-25/64" length by 1-1/2" width by 3-3/16" height.