The black Lens Covers for the Sigma Teleconverter Set from LensCoat are for the Sigma 1.4 TC-1401 and 2x TC-2001 extenders. They cover each extender with a 100% closed-cell neoprene coat, offering protection from bumps, jars and nicks. These coats allow the lenses to blend in with your surroundings and make you less noticeable to wildlife. They are useful for nature and outdoor photographers, as well as sports shooters and photojournalists.
Two small holes line up with the lens mount indicator, making it easy to quickly line up your extender with camera mount and lens with the cover installed. There's also a hole for the extender release. The matte black versions are designed to better blend in where desirable. Or, they can be used just for their protection value.