Product review (4 stars): doesn't work with windows 7 64bit operating system
Only certain serial numbers will work with Windows 7 64bit operating system. The software that comes with this datalogger is fine if you have Widows XP or vista if not download software from Extech website. This will work with Windows 7 32bit operating system but only newer dataloggers will work with the 64bit operating system. You will have to call them to find out which serial numbers are the newer ones.  The datalogger I recieved was older and wouldn't work.  I have had one of the older dataloggers and have used it for years and it is great. I just wish they had changed the name of the datalogger that works with Windows 7 64bit so that I would have known which model I was buying.