The small Gulfstream Tropical Mag-Float Floating Glass Aquarium Cleaner uses two a strong magnetic connection to allow easy and hassle free cleaning on the inside of the tank, all without getting a drop of water on your hands. With one half of the device on the outside and half on the inside, you can move the magnetic scrubber around the inside of the tank to eliminate build up of algae and other smudges that may accumulate over time. It's as easy as that! Simply guide the scrubber around obstacles and decorations in freshwater or saltwater aquariums without negatively impacting the sensitive inhabitants such as delicate coral. The magnets in this cleaner are made with high quality neodymium and will remain equally powerful over time and use. As well, the magnets do not retain debris, making it extremely easy to rinse and clean and can be left affixed to the side of the tank for easy retrieval. Keeping your hands out of the tank also helps you avoid introducing toxins or soaps from your skin into your fishes' ecosystem, and also helps in cleaning those hard-to-reach spots. The magnets are incredibly powerful and because of this, the thickness of the aquarium walls would need to be at least 3/16" (5mm) to guarantee no damage will come to the tank. This simple & effective cleaner is designed to save you effort, time and money on tank maintenance, making it a great accessory or gift for any aquarium owner. Suitable for tanks up to 30 gallons in size and is designed for use on glass aquariums only.