The Extech 42270 is an Additional Humidity and Temperature Datalogger for use with Extech 42275 and 42276 Kits. Datalogger measures temperature from -40 to 185 degree F (-40 to 85 degree C) and Humidity from 0 to 100 degrees. It can record up to 8000 readings of each parameter. Meter has a programmable sample rate of 1 second to 2 hours plus high and low alarm. A 42275 or 42276 kit is required to connect the datalogger to a PC for programming and data retrieval.