Measures and stores temperature (one channel for internal and another channel for external probe) and humidity readings. Some professional applications can be provided by the PC software DGraph. Logger status alarm indication and low battery indication are via flashing red/green LED and yellow LED. The button on housing can be used to start logging or confirm and clear LED alarm when LED alarm is hold status. User can plug data logger straight into PCs USB port without any cables. Before getting started user need to install USB driver and DGraph software provided on the CD which is included in product packing box. All the software can run under Windows XP Vista 7 or 8(32 bit and 64 bit Versions). User can easily use DGraph software to setup sample rate(from 10 seconds to 12 hours) high / low alarm limit and start / stop method and download data to PC etc. And then user can view analyse and print the data or export other file formats(txt xsl csv bmp jpg). Especially for some professional applications user can set access password name each channel enable/disable specified channel input calibration data for each channel disable LED indication for saving power and select sample mode(Instant Average Maximum and Minimum) etc. APPLICATIONS: This data logger is used mainly to monitor and verify humidity & temperature-sensitive goods equipments or areas. Example: Cold Chain Refrigeration Transportations HVAC Food & Pharmaceutical Warehouse; FEATURES: With an external temperature probe the length is 2m(or customized); Portable precise compact and low cost; USB interface directly communicate with PC for setup and data download; Unique and uniform PC control software: DGraph; Each unit has single serial number; User can set access password fo each data logger Alarm and status indication via LED; Start logging method: Immediately Button Start at Replaceable lithium battery and data is not lost if exhausted; Two point calibration for each channel; Alarm and status indication via LED Alarm limit settings for all channels; User can customize compound graph and new unit easily; User also can name each channel and enable/disable it; Waterproof grade: iP66