oh it's a basic indoor / outdoor thermometer from lowes, home depot or walmart. what you are 'supposed' to do with it is put the sensor on the outside and keep the base unit on the inside of your house. then you'll know the outside temp without going outside.
i hang the wire and sensor right off my light to where the plant tops are.
similiar to this: hxxp://www.lowes.com/lowes/lkn?action=productDetail&productId=263101-1308-00609&lpage=none
but that one is wireless. there are wired versions too.