This HID tubular metal halide light bulb offers an incredibly bright white light that can be used in closed luminaires in large commercial and industrial spaces.It is ideal for use in commercial floodlights. Fitted with a GES-E40 Goliath Edison screw (40mm) cap (sometimes known as a giant screw cap).The 400W light bulb emits an outstanding 40500 lumens of cool white 4100K light. Its long 15,000 hour life rivals many equivalent LED floodlights. The light bulb has an E40 giant Edison screw (GES) cap and universal operating position, so is compatible with many standard fittings.This discharge light bulb provides up to ten hours of light per start, with a three minute warm up time. It requires an external ignitor. For more details, please see the manufacturer\'s website.Please note, this light bulb is not suitable for dimming.For use in closed luminaries. Universal operating position.