だからなに? 3 This is to heat up a 5 gallon tank for my neon tetras, to prep them up for the coming winter. After several hours of usage, there was negligible difference in water temperature. I had to test the device and found that it did produce heat, although probably not suitable for a tank this size. But 5 gallon is not a big tank lol.The suction cups are pretty strong, so removing them was quite difficult, which can both be a good and bad thing. I also wish it was smaller because it is hideous.The item arrived quickly, about 2 days after it was ordered.