Add an eyebolt and string or cord to any Alnico magnet and retrieve small metal items in swimming pools, window wells, crawl spaces and more. Use as work holding devices for wood cutting, sign making or other hobby applications. Alnico button magnets have a convenient center mounting hole and each comes with metal keeper to retain magnetic strength. More About Alnico: Made from aluminum, nickel, cobalt and iron, alnico is primarily used for magnetic applications requiring a high heat tolerance.