This device sounded promising, but it only allows settings by whole degrees of temperature, so 99.5 cannot be done. If you don't mind that, it seemed to hold a temperature and humidity level pretty well, but I like to set at 99.5 and then 98.5 at lockdown, so it is not good for me. In addition, it is very hard to set up as the instructions are written very poorly. My husband is an electrician, and used to reading complex diagrams, and even he was frustrated with trying to get it set up. I am keeping it as a back-up, mostly because I think it would be a bother to return. It will be good for someone using it for a less delicate purpose.