The Sigma USB Dock for Nikon Lenses allows you to connect your Sigma Global Vision lenses to your computer in order to update firmware and adjust focus setting parameters using the Sigma Optimization Pro software.
Sigma USB Dock Features
Sigma Optimization Pro: Once a Sigma Art, Contemporary, or Sports line lens is connected, you can use the Sigma Optimization Pro software to configure focus settings and update lens firmware
Focus Settings: For all lines of lenses, there are four categories for prime lenses and 16 categories (four options for focal length, four options for shooting distance) for zoom lenses available
Sports Line-Specific Settings: If using a Sports line lens, additional lens configurations are available: three different AF speed modes to modify how quickly the lens changes focus; the ability to constrain focus distances within a specific range to suit your personal shooting habits