Tokina 11-16mm f2.8 DX II is an Auto Focus (AF) Wideangle Zoom lens with APS-C / DX max sensor coverage. When mounted on a APS-C / DX sensor camera, it will give you an FF equivalent focal range of 16.5 - 24mm. With a max aperture of f2.8, this lens is fast on wide end and equally fast at 16mm with a max aperture of f2.8.
Tokina 11-16mm f2.8 DX II is not a weather sealed lens, so you have to be extra careful against rain and dust. Tokina replaced the older Tokina AT-X Pro 11-16mm f2.8 DX Canon EF with this model. Follow the link to read our detailed comparison of these model: Compare Tokina AT-X Pro 11-16mm f2.8 DX II Canon EF vs Tokina AT-X Pro 11-16mm f2.8 DX Canon EF