Lumatek 315W Ceramic Metal Halide lamps (also known as CMH / CDM / LEC) are available in 4200K Daylight and 3100K Agro formats. The PCA ceramic arc tube allows the lamp to operate at higher internal temperatures increasing color rendering, yield and efficiency. PCA resists interaction with chemicals within the tube which stabilizes the chemical mixture over the life of the lamp, thereby improving color consistency and PAR/PPF level maintenance. Pulse-start technology allows for faster startup and restart times, longer lamp life, and increased lumen maintenance.