Solar Powered and Auto On/Off: Powered by solar energy with no extra electric cost or battery replacement needed. The light sensor charges the lights during the day and turns them on automatically at night 8 Modes and Memory Function: Use the On/Off and mode buttons to select from 8 lighting modes. The built-in memory chip saves your last mode setting, so you don t need to reset it daily Waterproof: With an IP65 rating, these solar Christmas lights are designed to withstand all weather conditions, including heavy rain and snow, making them suitable for indoor and outdoor use Easy to Install: 4 Pack ,each string 39 ft (including 6.5 ft lead cable) with a solar panel and ground stake is ideal for wrapping around trees or decorating various outdoor spaces. Ensure the solar panel is exposed to sunlight Widely Used Solar String Lights: These solar-powered string lights are perfect for Halloween, Christmas, weddings, holidays, gardens, yards, lawns, fences, porches, trees, roofs, and decks.