Basic stainless steel has a 'ferritic structure and is magnetic, formed from the addition of chromium – it can be hardened through the addition of carbon, making it 'martensitic'. However, the most common stainless steels are 'austenitic' – these have a higher chromium content, and nickel is also added. Specifications: Usage/Application: Box Magnet Material :Stainless Steel Magnet Grade: N35, N38, N40, N42, N52, N45 Brand: jr strong magnet Coating: Ni or zn Size/dimension: D3-30 Package Includes: 1 x Stainless Steel Small Magnets For Box Magnet