【BEARABLE TRACTION】 25 lbs tension of black magnetic hooks is based on the direction of tension perpendicular to the contact surface -- reduced by 2/3 if used horizontally. Please note that the tension of the magnet hooks is also affected by the direction, the material of the contact surface and other factors..【SUPERIOR MAGNETS COATED】 Hooks magnets for classroom are coated with three layers of Black epoxy+ Nickel+ Copper, which provides a shiny and rust resistant coated steel cup provides protection for the magnets with hooks and helps to prevent chipping or cracking..【HIGH QUALITY】 The black magnet hooks for refrigerator is composed of neodymium magnets and high quality A3 steel. Due to the addition of an iron shell, the suction of strong magnetic hooks is several times that of ordinary metal hooks. Metal magnetic hook, strong magnetism forever!.【VARIOUS USES】 Magnet hooks for classroom are easy to install and use because of its simple structure.Strong magnetic hooks for hanging are ideal for hanging small objects in places with iron or steel, such as cruise cabins, home, school, workshop, indoor and outdoor..【PROFESSIONAL SERVICE】 We are a magnet supplier with professional strength. You can certainly find magnetic hooks you want in my shop! If you need mass customization of magnet hooks for hanging , contact us and we can meet your needs.