High quality corrosion resistant stainless steel blade material. Allow Magnet Scraper stay in your tank without rusting.*3 in 1* function:1. Bayonet Style Scraping Blade for Removing Stubborn Algae.(High Grade Anti-Corrosion Stainless Steel Blade for Glass and one ABS Blade for Acrylic Tank),2. Algae Scrubbing Pads (General cleaning),3. Thick foam Pad for finely polishing (Optional : Floatable, Removable and easy to install. Soft and very acrylic safe cleaning pad that will remove all of the dust-like algae without scratching)