Review on Hygrometer Thermometer Temperature Humidifiers Greenhouse by Karla Schwinden

Just opened the box and most seem to be working fine. On the other hand, 3 of the rectangular ones (on the right) have something like dead cells or something. Where it just doesn't show them. You only have to use them for the parts they display correctly which is a little disappointing but the price was really good so it's ok. As I just received them I don't know how long they will last, they are always on not off switch I could see. Another note, they are all individually wrapped, seems a little pointless?