Tokina 10-17mm f3.5-4.5 Fisheye 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 15 - 25.5mm. With a max aperture of f3.5 at 10mm, we can not consider this lens fast on wide end and neither at tele end with its f4.5.
Tokina 10-17mm f3.5-4.5 Fisheye is not a weather sealed lens, so you have to be extra careful against rain and dust.