Sigma TC-2011 Teleconverter L-Mount

Sigma's TC-2011 Teleconverter is specifically designed for use with Sigma L-Mount lenses. When mounted between your lens and camera body, this teleconverter will increase your focal length of your lens by 2x. It is constructions from 8 elements in 4 groups, is splash and dust-proof as well as being able to maintain effective autofocus across your entire focal range and through all apertures.

Price: 399.99 from Wex Photo Video