OptiCore LED Christmas light bulbs are the state of the art for durability, beauty, brilliance and color. The lens is made of polycarbonate, up to 200 times stronger than glass, which makes OptiCore bulbs virtually unbreakable. The lens is also 115% thicker than ordinary bulbs, allowing the light to infuse the lens with rich, vibrant color. 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 OptiCore's durability, energy efficiency and beauty, these may be the last replacement bulbs you ever need. They'll give you elegant light and beautiful color for years. Don't trust your most special occasions to anything less than OptiCore from Wintergreen Lighting.