Non-scratch, dual surface algae pad perfect for glass and acrylic aquariums. Melamine foam side uses micro abrasive technology to easily remove algae from the sides of your aquarium, while the durable scrubbing side allows you to attack the rougher grooves of rocks and driftwood. Effectively removes algae from scratches. Plus, the color of the pad contrasts against dark algae making it easier to see when areas are fully clean. No soaps or detergents needed. Measures 4.5" x 2.5".