Strong Magnet: This Aquarium Magnetic Glass Cleaner, Built-In Double Magnet. When You Move This Magnetic Aquarium Brush, When You Move The Small Outer Aquarium Brush, The Magnetic Brush Inside Follows: Quickly And Easily Cleans Away Algae Growth To Keep Your Aquarium Healthy And Looking Its Best. Non-Slip Handle: Improved Soft Grip Is Contoured, Non-Slip, Comfortable, Saves Time And Money. Note: Not Suitable For Acrylic Aquariums And Low Iron Glass AquariumsRemoves Algae And Does Not Damage Glass: The Side Of The Scrubbing Handle Is Covered With Felt So That It Glides Easily When You Move It, The Other Side Is Made Of Fabric With Tiny Hooks That Scrape Algae Without Damaging The Glass.Floating Design: The Interior Brush Won'T Sink Into The Farthest Depths Of The 'Aquarium. Convenient To Use.Size: M (10.5 X 4.8 X 7.5), Glass Thickness (Less Than 6Mm)