Nikon 200-400mm f4G ED VR II is an Auto Focus (AF) Telephoto Zoom lens with 35mm FF max sensor coverage. When mounted on a 35mm FF sensor camera, it will give you an FF equivalent focal range of 200 - 400mm. With a max aperture of f4 at 200mm, we can not consider this lens fast on wide end but f4 at 400mm is not too bad for tele end.
This lens features on optical image stabilization which helps capturing sharper images at lower shutter speeds. Nikon 200-400mm f4G ED VR II is weather sealed which makes it an ideal lens for outdoor use, especially when coupled with a weather sealed camera body. Nikon replaced the older Nikon AF-S Nikkor 200-400mm f4G ED-IF VR with this model. Follow the link to read our detailed comparison of these model: Compare Nikon AF-S Nikkor 200-400mm f4G ED VR II vs Nikon AF-S Nikkor 200-400mm f4G ED-IF VR