What makes Earth Worth Ceramic Sockets so special? Quality and Performance! Earth Worth only supplies the highest quality ceramic grow lamp sockets. We have searched the world over and partnered with a factory which utilizes the most advanced materials and quality control standards which results in a high performance, long lasting, and versatile ceramic sockets that will offer safe, continued service for years to come. What is Included: One (1) Ceramic Grow Lamp Socket. Features: Fit for E39 bulb cap. Easy to install if you need to change your reflector. Ceramic socket should be used with ballast for steady power supply. All compoments are UL listed. Prewired, ready to install. Suitable for most remote ballasts in the market.