Jasonwell Magnetic Aquarium Fish Tank Glass Algae Glass Cleaner Scrubber Floating Clean Brush Clean algae and scum off of the inside of your aquarium the easy, fun way! 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. Simply drag the no-scratch, felt-lined handle and inside your aquarium, the scrubber follows, cleaning as it goes 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.THE LARGER,TEH STRONGER TEH MAGNET. This product comes with a 2-year warranty and 100% money-back guarantee.