Flipper Standard can be used on glass or acrylic tanks up to 1/4 - 1/2 (6 - 12mm) thickness;Patented design that flips from scrubber to scraper. Complete cleaning without ever getting your hands wet!;Unique orienting buoyancy for easy retrieval of the cleaner every time.;Ultra low profile design allows cleaning in hard to reach areas of the tank.;Blades are interchangeable and replaceable