Say hello to the next generation of LED Christmas lights: OptiCore, superior bulbs that offer unsurpassed beauty, ruggedness and reliability, with all of the brightness and color saturation of vintage Christmas lights. The lens is made of polycarbonate, up to 200 times stronger than glass, making OptiCore bulbs virtually unbreakable. The lens is also 115% thicker than ordinary bulbs, allowing the light to infuse the lens with rich, vibrant hues. Inside, the SMD LED diode produces brilliant light that saturates the lens evenly for a uniform appearance from every angle. And OptiCore bulbs will last for years; they boast an average bulb life of 60,000-hours. With OptiCores durability, energy efficiency and beauty, these may be the last C7 replacement bulbs you ever need.