C9 25' Magnetic string on 12" Spacing used for homes, office buildings, barns, and restaurants. These magnetic sockets will adhere to any ferrous metals (Iron and Steel) making for quick installations since there is no need for Christmas light clips. Perfect for rooflines, building flashing, and gutters. No need for screws, glues, clips - just adhere the magnetic C9 socket to your metal surface saving time and labor cost. We use Neodymium grade magnets which are the strongest magnets available. Each magnet is plated with a nickel protective coating which prevents rust.