Permanent data storage, documents for searching, data could be read and by PC data management software. Directly connect with computer for data exchange, easy operation: When connected to computer, the software will automatically read data, and form reports. Display temperature, time, over temperature alarm, temperature /lower limit, temperature Max./Min. value in the LCD screen. Double sensor: Built-in Sensor and External Sensor-Besides battery, could also be powered by USB cable when connected with PC, and it could upload data even if the battery is out of use. Over Temperature Alarm & /Lower Limits can be set-Used to record temperature data over a long period of time-Wide measuring range, high accuracy & adjustable record interval-LCD to show data and settings-Above one year battery life-16000 data recording capacity-Data management software & USB cable included for working with PC -Data can be downloaded, analyzed, exported and conveniently. Auto power off and low battery indication-It has internal temperature sensor, and with optional external sensor, with optional internal buzzer alarm. If external sensor is connected, temperature measuring will automatically switch to the external temperature sensor. It has one 2450 battery, with the battery compartment in the back, ease of battery replacement: Rotate the battery cover clockwise to remove the battery by a coin, and rotate and tighten the battery cover counter after battery replacement. Specifications: Temperature measuring range: -30 C~+60 C for optional external sensor: -40 C~+85 C environmental temperature: -30 C~+60 C Accuracy: +/-1 C Resolution: 0.1 C Record capacity: 16000 points (MAX) Record interval: 10s~24hour adjustable Sensor: Internal NTC thermal resistor Communication interface: USB interface Power supply: CR2450 battery or power supply via USB interface Battery life: in normal temperature, if the record interval sets as 15 minutes, it could be used above one year. Item Size: . 84 (L) x 44 (W) x 20 (H) mm (3.3 x 1.73 x 0.79 inch) Item Weight: . 60 g Package: 1 x Data 1 x CR2450 battery (Installed inside) 1 x External Sensor 1 x USB Cable 1 x Instruction Manual Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.