The Antique DIALCO 20 Light TWINKLING SET Transformer CHRISTMAS color bulbs with box is a vintage string light from the 1950s, featuring multicolor incandescent bulbs with a C6 bulb shape code. This indoor lighting set is perfect for Christmas and comes with a corded electric power source. The TWINKLING feature adds a festive touch to the original set, making it a charming addition to any holiday decor. Made in the United States, this collectible piece is sure to bring a nostalgic glow to your home during the Christmas season.