The Flipper Nano can be used on glass tanks up to 6mm (1/4") thickness or about 25 Gallons. Flipper's patented design creates the only 2 in 1 aquarium cleaner that can FLIP from scrubber to scraper simply by rotating the handle. Complete cleaning without ever getting your hands wet! It is the only aquarium cleaner you will ever need! Flipper Features Made with rare earth magnets for incredible cleaning strength and durability. Cleans even the most stubborn coraline algae. Blade side has only 3 contact points resulting in a 3mm gap between the cleaner and the glass. This minimizes the chance of trapping sand, and thus reduces the chance of scratching, even when cleaning below the sand!. Unique orienting buoyancy always keeps the magnets facing the glass for easy retrieval. Plus, Flipper is nearly neutral buoyancy so it does not sink like a stone if the magnets are disengaged. Includes Stainless Steel blade for glass tanks. It is suggested to replace blades every 3-6 months to maintain optimal algae scraping. Designed for smaller tanks - Up to 1/4" (6mm) or 25 Gallons