Canon 24-70mm f2.8L II USM is an Auto Focus (AF) Standard 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 24 - 70mm. With a max aperture of f2.8, this lens is fast on wide end and equally fast at 70mm with a max aperture of f2.8.
Canon 24-70mm f2.8L II USM is weather sealed which makes it an ideal lens for outdoor use, especially when coupled with a weather sealed camera body. Canon replaced the older Canon EF 24-70mm f2.8L USM with this model. Follow the link to read our detailed comparison of these model: Compare Canon EF 24-70mm f2.8L II USM vs Canon EF 24-70mm f2.8L USM