Spools & Stringer Clips, Stakes & Electrical C9 & C7 Bulbs C7 led bulbs C9 led bulbs Spools & Stringer Christmas String Lights Menu Clips, Stakes & Electrical C9 & C7 Bulbs C7 led bulbs C9 led bulbs Spools & Stringer Christmas String Lights Spools or stringers are for screwing C7 & C9 led bulbs. In USA, they usually use SPT-1 18A wire for it. The most popular Spools sockets are with ” AD ” logo, we make it ! Read more E17 spools for C9 bulbs Read more E12 stringer for C7 bulbs