Features: Ideal for metal recyclers, brokers, antique buyers, collectors, or anyone who needs a convenient, easy-to-carry magnet to test for iron, nickel, or cobalt content. Identify fake or plated jewelry, which often has steel or nickel alloys as the base material (some alloys, like nickel-silver and German silver, are non-magnetic despite containing ferrous metals). The magnet test is typically the first step before density and acid testing. Distinguish chrome-plated items from polished aluminum, silver, and non-magnetic grades of stainless steel (chrome plating requires a nickel layer, which is magnetic). Identify and sort solid brass and bronze from steel-plated items (useful in the antique market and hardware stores). Specifications: Material: Iron Size: Base 1: Approx. 12mm / 0.47 inch (maximum pull-off force 4kg) Base 2: Approx. 15mm / 0.59 inch (maximum pull-off force 9kg) Base 3: Approx. 17mm / 0.66 inch (maximum pull-off force 13.5kg) Base 4: Approx. 21mm / 0.82 inch (maximum pull-off force 17kg) Shell plating: Nickel, Copper, Nickel Adsorption direction: Magnetized on the bottom only Use temperature: Not higher than 75C Note: Please allow 1-2 cm errors due to manual measurement. Please ensure you are comfortable with this before ordering. Due to differences between monitor displays, the picture may not reflect the actual color of the item. Package includes: 1 x Keyring