The Ultra Sun? 1000 Watt Metal Halide DE 10,000ø K lamp emits higher-intensity blue and violet spectrums with a significant increase of beneficial UV wavelengths. Often used during the last one to two weeks of growth, for the final ripening at the end of your plants' flowering stage. Specifically designed for high frequency DE ballasts. DE lamp construction incorporates the electrical connection at each end of the lamp, removing the need for a frame inside. The absence of the frame eliminates shadows in the beam. For horizontal operation only. The jacket of this lamp is made from quartz glass. Oil from your hands can damage this lamp. Must be used in an enclosed fixture with a protective lens. Do not operate in an open style luminaire.