A used version of the the KeyTag Kt1LcdMu. It is an extremely accurate multi-use temperature data logger with a detailed, multi-screen display. Every KeyTag Kt1 will be individually calibrated before it leaves us and will be delivered with a calibration certificate. The certificate can be found in the PDF file generated by the logger. Once plugged into the USB port the logger works like a USB stick. To read the automatically generated files, use the default office software. To program KeyTag data loggers, use the free KeyTag Manager Software. The Logger works just like a brand new KeyTag.