I've seen them, and think its a great product for certain people that can't check on their frogs that often. But I check my enclosures a lot(mostly because they are in my bedroom at the moment) and I'm usually aware of a humidity drop. Also, my enclosure holds humidity really well, and typically every few days it needs to be watered so I don't have to worry about doing it multiple times a day(thank god). If I come across a good deal on one I might pick one up, but I really don't "need" it. Would be nice though lol