These LED Panel Lights are the same size with your twin Fluorescent tube fittings. IE. 1200×300 mm or 600×600 mm fluorescent light fitting. The sizes are also available in 600x300mm and 300x300mm, Circular Panels in 240mm, 180mm and 100mm diameter are also available to meet other applications. They are slim line fitting (9 mm) so they can be fitted into most ceilings.