Holds C9 socket and bulb vertically or horizontally Securely attaches bulbs to any ferrous (magnetic) metal surfaces Strong magnetic connection holds up in all weather These clips are for traditional C9 sockets Don't let your metal hardware go bare this holiday season. These magnetic intermediate base C9 socket caps slip on easily to convert plastic light string sockets to magnetic ones. They are perfect for use with metal roofs, gutters and gates. Let your fences and gates be merry and bright with their own holiday lights this season.