I purchased this at an auction and I'm not sure how old it is or even if it is old. I know the box it came is looked old. The paper work that came with it said, The Ohio Thermometer. It also says, if incubator thermometer reads: 102f add 2% to hygrometer reading. Example: if your standard incubator thermometer reads 103 and your hygrometer reads 50, at 102 your hygrometer reading 50 would be read 52. I was going to put it in my bator but I don't understand the above. Any idea's would be appreciated.