They are brand new batteries. But I found out from watching it for a little while that the all living things is extremely sensitive. Eventually when the mist settles they read withing 3% of each other. If you spray a little near the all living things it jumps up to 100% then settles after 20 mins but with the acurite I get a solid reading after 2 minutes so I'm just removing the alt humidity probe. Since the temperature probes of the 2 devices are withing 1.5 degrees I think I'm going to use one for directly on my Kane heat mat and one on top of the substrate so I can get both readings. Just waiting for my v400 and mistking from lllreptile and then I can set everything up. Little did I know though is that lllreptile doesn't ship the vision cages from there warehouse. It comes directly from vision. According to vision website it takes 2-4 weeks ugh.