Pentax DA 55-300mm F4.0-5.8 ED WR is an Auto Focus (AF) Telephoto 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 82.5 - 450mm. With a max aperture of f4 at 55mm, we can not consider this lens fast on wide end, and it is slow at the tele end with its max aperture of f5.8.
Pentax DA 55-300mm F4.0-5.8 ED WR is weather sealed which makes it an ideal lens for outdoor use, especially when coupled with a weather sealed camera body.