1:SUPER POWERFUL - This fishing magnets adopt strong neodymium magnet for its base. 2: - The powerful magnetic force is only concentrated at the bottom, The other three sides are Protected by steel cups that almost no magnetic force and magnetic force equivalent to 10 times the volume of the same magnet. force permanent, long service life. Made under ISO 9001 Quality Systems. 3:BEST COATING - Ni+Cu+Ni Triple Layer Coated. The Best Coating Available, which Provides a Shiny and Rust Resistant Coated steel cup provides protection for the magnet and helps to prevent chipping or cracking. 4:MULTI USE - Unique design with Countersunk Hole and Eyebolt Great for salvaged of various iron-containning nickel material underwater and Good idea for magnet fishing, lifting, hanging, retrieving applications. Have fun to searching items like eyebolt, screws, hooks, fasteners and so on in your warehouse garage or yard. 5:PERMANENT STRENGTH - Neodymium is a kind of rare earth metal, it's suitable for making permanent & powerful magnets. This fishing magnet has permanent magnetism, it will be the same powerful even decades after. specification: 1. Shape: round 2. Material: NdFeB magnet + A3 steel + 304 stainless steel 3. Color: silver 4. Maximum vertical tension D16mm: 5KG/10LBS D20mm: 9KG/19LBS D25mm: 19KG/41LBS D32mm: 32KG/70LBS D36mm: 41KG/90LBS D42mm: 61KG/134LBS