Sigma 100-400mm f/5-6.3 DG OS HSM is a zoom lens compatible with Canon cameras. It has a maximum aperture of f/5 and a focal length range of 100-400mm. The lens has both auto and manual focus modes and comes with a mount for Sigma cameras. It is a part of the Sigma Contemporary series and is compatible with 67mm filters. The lens is designed to provide sharp and clear images, making it suitable for wildlife, sports, and other outdoor photography.