Opteka External Flash Battery Pack for Nikon SB-900, SB-800, SB-11, SB-20, SB-22, SB-24, SB-25, SB-26, SB-27, SB-28, SB-28DX, SB-80DX Speedlight Flash Units External power source for higher flash capacity Reduces recycle time by 60-75% Powered by 6 AA batteries (not included) Includes padded carry case Dimensions: 6.88CM X 15.79CM X 2.48CM (W X H X D) Weight: 170g (without batteries)