These bulbs fit traditional C9 parallel-wired Christmas light cords with E17 bases. Their smooth finish is shiny like glass but durable polycarbonate lenses easily survive an encounter with concrete. Use them to replace incandescent bulbs and see electric bills decrease by up to 90%. Sold in bags of 25, prices are per bulb. Shipped without cords, see a full line of C9 cords and spools to complete your Christmas display. Common sense notice: Do not run more than 250 feet of 18 AWG light line in a single run.