This is a panel warmer for amphibians and reptiles, specifically for small aquariums. I received Hercules beetles and other beetles from an acquaintance who breeds them, and I used this to help them overwinter. I checked it recently for this listing and it works without any problems. However, there are marks left from tape on the back, so please be aware of that. On the website where I purchased it, the large warmer currently costs 4300 yen, and the small aquarium one was 1520 yen at the time.