From Nikon's website: The SB-910 is a high-end Speedlight for advanced amateur to professional photographers that offers a number of improvements over its predecessor, the Nikon Speedlight SB-900. Among these improvements are smoother operation, greater illumination precision, and the adoption of hard color filters. The SB-910 fully supports the creative photography of advanced amateurs to professionals who demand the ability to make the most of light to achieve their individual intent.