OptiCore smooth Christmas light bulbs re-create the rich color and warm beauty of incandescent vintage Christmas lights, but with all the advantages of LED. The smooth lens is made of polycarbonate, which is 200 times stronger than glass. This makes OptiCore bulbs virtually unbreakable. The SMD LED, which is housed within a reflective core, spreads light evenly through the polycarbonate lens for rich, saturated color. And with an average lifespan of 60,000-hours, these are bulbs that will last for years. Get the energy efficiency and durability of LED with all the richness and color of old-fashioned Christmas lights in these OptiCore LED smooth/opaque Christmas light bulbs.