M-Audio 9900-40822-00 Keyboard Cover High-performance L-series super-telephoto lens series with built-in dual-mode Image Stabilizer (IS) function Ultra-high image quality through the use of Fluorite and UD Glass Super-high AF speed with improved Ring USM (Ultrasonic Motor) and new algorithms for focus prediction with moving subjects Focal Length & Maximum Aperture - 400mm 1 - 2.8 Lens Construction - 17 elements in 13 groups