This was not sensitive or quick enough to work well enough for me. I imagine since the switch is housed within a plastic box the external temperature has to be extremely high rather quickly or above the target temperature for long periods of time. A lower temperature might have worked for me but as they don't produce those I had to go with a more precise (expensive) solution

works as stated,high quality

I didn't really have time to sit down on the computer, or to go through your catalog. All I knew was I had to do something, and soon. I went up into the walk-up attic and even with a ridge-cap roof, it was getting way way too hot up there. I needed a fan that knew when it had to turn on, and know when to shut itself off. I put a large analog thermometer up there and checked the following day. It was nearly pegged out, or greater than 120 degrees. I talked to your customer service department, and told them what I needed and my situation. They mentioned item number blah blah blah and it turns on @ 120 degrees. Yes! I have a lot of mint condition toys up there in the attic including Chucky and Tiffany. Did not want them melting or warping as a lot of the toys up there are plastic. It sounded like it was just what I needed so I ordered it. I was very pleased with how quickly it arrived. I wired everything up and we've had temp's in the 90's for over 9 days in a tall corn row. It was just shy of 121 degrees and the fan started up just like it was supposed to. It also shut off when it was supposed to, so that fan did not have to run all night. I will definately be needing another one but probably won't because there's no electricity on that end of the attic, yet. And that's that. A happy customer. Stay cool, drive less.