The SC-29 Off-Camera AF TTL Cord which mounts to the hot shoe on Nikon digital and film SLR's enables an attached Speedlight to accurately autofocus in low light no matter where it's placed for beautiful shadowless lighting. This 1.5m (4.9ft) coiled cord incorporates a new AF Illuminator on the remote flash mounting shoe which overrides the Speedlight's AF Illuminator to eliminate any possibility of autofocus discrepancy when using a Speedlight off-camera. In addition the SC-29 can be used with the SB-800 Quick Recycling Battery Pack as an off-camera master controller in a wireless multi-flash setup. Other Nikon Speedlights can also be used remotely with the SC-29. They will retain the automation and TTL functions as if the flash was mounted directly onto the camera's flash shoe but the SC-29's AF illuminator will not operate. Nikon's professional-quality TTL multiple-flash system is designed so that even a novice can use it with confidence right away. You'll be able to create stunning effects and always get perfectly exposed pictures. Plus there's no need for complicated manual exposure-value calculations or accessory flash meters.