Canon 14mm f2.8L USM is an Auto Focus (AF) Wideangle Prime lens with 35mm FF max sensor coverage. When mounted on a 35mm FF sensor camera, it will give you an FF equivalent focal range of 14mm. With a max aperture of f2.8, this is a fast lens.
Canon 14mm f2.8L USM is not a weather sealed lens, so you have to be extra careful against rain and dust. Canon 14mm f2.8L USM was replaced with Canon EF 14mm f2.8L II USM. Follow the link to read our comparison of these cameras:
Compare Canon EF 14mm f2.8L USM vs Canon EF 14mm f2.8L II USM