Mark, Three years ago we installed fifteen Hobo U12 units (records temperature, relative humidity and light levels) in exhibit areas scattered about the airport system. I walk around quarterly with a laptop and a cable to download the contents of each and re-launch them on site. They have been very easy, reliable and they are not expensive. The software has been good, too. If they record the type of information you need to have I recommend them. Onset Computer Corporation: http://www.onsetcomp.com/products/data-loggers Good luck, Sheila Sheila Kollasch, Museum Assistant Phoenix Airport Museum 3400 Sky Harbor Blvd. Phoenix, AZ 85034-4403 602-683-3647 FAX 602-273-2702 [log in to unmask] “The most beautiful thing we can experience is the mysterious. It is the source of all true art and science.”—Albert Einstein