Be confident in your purchase, we are a Certified Algae Free Dealer, how cool is that?!? With properly sized magnets and now includes the scraper attachment, Algae Free has made one of the best algae scrapers in the industry. Most of their value is the fact all of them (except the Great White) do float if the connection through the aquarium is lost for easy retrieval, which is the frustrating point for most other magnet cleaners in the industry. The new "Plus Series" has a detachable and replaceable scraper blade for glass (stainless steel) or acrylic (plastic) aquariums and will make algae cleaning quick and easy. Our cleaning magnets are made with Neodymium Rare Earth Magnets, one of the strongest magnets in the world! Algae Free LLC don't use surplus magnets -- only new. All of our cleaners are made of the finest, safest and most cost-effective materials available. The outer magnet assembly is handcrafted in the USA. Strong, high-quality neodymium rare earth magnets Replaceable scraper blades for glass and Acrylic aquariums Replaceable inner scrubbing pad with nontoxic adhesive backing Replaceable felt pads for the outer cleaning assembly Floating interior magnet assembly (except Great White models) Inner assembly is non-toxic and can be left inside tank all the time -- it will not rust! Can be used on all glass aquariums Acrylic-safe inner scrubbing pads make it ultra safe to use on acrylic aquariums Can be used in fresh and salt water Decorative finish that becomes part of your aquarium Limited 2-year warranty on material and production defects Fitment: The Hammerhead is Algae Free?s most popular magnetic cleaner. It works great on almost all glass and acrylic tanks up to 5/8" thick. Glass aquariums holding up to 110 to 200 gallons Acrylic aquariums 48" long and 30" high Large 4" x 2" cleaning area