Pentax 16-45mm F4 ED AL is an Auto Focus (AF) Standard 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 24 - 67.5mm. With a max aperture of f4 at 16mm, we can not consider this lens fast on wide end but f4 at 45mm is not too bad for tele end.
Pentax 16-45mm F4 ED AL is not a weather sealed lens, so you have to be extra careful against rain and dust.