The dedicated APO teleconverters can be mounted between select lenses and the camera body to increase the focal length by the power of 2.0x. The new multi layer coating reduces flare and ghost, which is a common problem with digital cameras. They demonstrate best performance with DG series lenses. They also offer maximum photography magnification by 2.0 x, without any variation in the minimum focusing distance. Compact and lightweight, these teleconverters convert your lenses into longer focal-length lenses, so you don't have to do a lot of unnecessary footwork.

Body & rear lens caps and carrying case are included with the teleconverter.

Use the below link to see if the converter is compatible with your lens

http://www.sigma-photo.co.jp/english/acc/condaitr.htm