Professional quality aquarium scrapers with plastic blades that don't scratch glass or acrylic aquarium surfaces. Tough enough to scrape away the hardest coralline, green algae, or diatoms. Ideal for use on marine reefs or any freshwater system. The only products on the market that will remove algae from old scratches in glass tanks. Combos allow you to reach up to 50" - that means you can scrape away previously inaccessible debris and algae. Durable glass fiber Extensions attach to Pro-Scraper Long and X-Long with an adjustable non-slip ABS fitting. Combos include one Pro-Scraper and one Extension.