These unique top brand lamps are designed to work with either SON or Mercury fittings, & give you the same quality of light associated with metal halide. This makes them ideal for factories, retail & sports halls, where light quality is essential. Specifications We stock these lamps in both 250 watts & 400 watts versions. The fitting is Large Screw. Suitable for fittings that already have an ignitor. Hassle free As these lamps have the flexibility of working in a variety of different types of fittings, you can keep your existing fittings & vary the types of lamp you use, giving you complete control. Their long life of up to 15, 000 hours on average means they will give you bright light for years, before they need replacing. You can change your mind Most of our products are covered by our Change Your Mind guarantee, meaning if you order something but want to return it, we'd be happy for you to do so. Simply look up the guide on this website.