Saim Magnetic Aquarium Fish Tank Glass Algae Glass Cleaner Scrubber Floating Clean Brush Can be used on glass tanks up to 0.12" - 1.14" (3 - 29mm) thickness. Strong magnetic forces cause the inside cleaning brush to follow the outside handle. Just wipe the outside, and the inside is cleaned! The inside piece floats, so if it becomes separated from the outside piece, it's easy to retrieve. Dimensions: 4.5" x 2.7" x 2.8"/11.5 x 6.8 x 7cm(LxWxH); great for large glass aquariums IMPORTANT: Made for common glass fish tank. Not for acrylic and low iron glass. Please choose the size by the thickness of your fish tank glass.