Check the listing for details. Seachem Duo Pad Algae Scrubber Micro Abrasive Safe for Glass & Acrylic Aquariums. Condition: New. Listed at 10.99 USD. Seachem Duo Pad Algae ScrubberMelamine Foam, Micro Abrasive Technology with Added Durable Scrubbing Surface.Safe for Glass and Acrylic.No Soaps or Detergents.Effectively Removes Algae From Scratches. Overview:The Seachem DuoPad is a non-scratch, dual surface algae pad for glass & acrylic. The 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. It is particularly effective at removing algae from scratches. It is chemically inert and does not use soaps or detergents. It's white color contrasts against dark algae making it easier to see when areas are fully clean. More on Melamine:Melamine foam is incredibly effective abrasive cleaner. It has a microstructure as hard as glass, but because of its open-cell structure it remains flexible. It performs on stains a lot like extremely fine sandpaper. In the aquarium, it easily removes algae by scraping with its extremely hard microscopic filaments.Size: 4.5" x 1" x 2.5" (1 Pack)