Pentax 40mm F2.8 Limited is an Auto Focus (AF) Standard Prime 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 60mm. With a max aperture of f2.8, this is a fast lens.
Pentax 40mm F2.8 Limited is not a weather sealed lens, so you have to be extra careful against rain and dust.