The Nikon SC-29 Off Camera AF TTL Cord easily mounts to the camera’s hot shoe and enables an attached SB-800 flash to accurately auto focus in low light when placed on a flash bracket. Great for beautiful shadowless lighting. The cord uses a new AF Illuminator at the mounting point that overrides the SB-800’s AF Illuminator. This completely eliminates any possibility of autofocus discrepancies when using the SB-800 off camera. The SC-29 TTL cord with the SB-800 quick recycling battery pack can also be used as an off camera master controller in a multi-flash set-up.