Dymax Mag-Scraper is a float type magnetic scrap and scrub device that make aquarium maintenance easier and quicker without submerging hand into water. This product is made of strong and reliable material which is suitable for both freshwater and marine aquarium use. The Mag-Scraper includes two attachable plastic scraper blade that helps remove stubborn algae or debris from the glass surface. Size M: For glass thickness 10-16mm