This HID elliptical metal halide light bulb offers an incredibly bright white light that can be used in open luminaires in large commercial and industrial spaces.The light bulb has a 15 operating position, so is suited to vertical (or near-vertical) fittings. Fitted with a GES-E40 Goliath Edison screw (40mm) cap (sometimes known as a giant screw cap).The 400W light bulb emits an outstanding 41900 lumens of neutral white 3700K light. UV stop glass prevents the light bulb from discolouring over time, and its long 20,000 hour life rivals many equivalent LED floodlights. The light bulb has an E40 giant Edison screw (GES) cap, so is compatible with many commercial fittings.This discharge light bulb provides up to ten hours of light per start, with a two 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.Suitable for open luminaries. 15 operating position.