Thank you for viewing. This is the TTL flash cord Nikon SC-29. I'm selling it because I don't use it much anymore. This cord is used for TTL auto flash photography (with AF assist light function). ● Use it to perform TTL auto flash photography with the flash units SB-5000, SB-910, SB-900, SB-800, SB-700, SB-600, SB-500, SB-400, SB-300, etc., away from the camera (1.5m). ● Equipped with an AF assist light, it can emit AF assist light from the SC-29's camera connection unit when combined with SB-5000, SB-910, SB-900, SB-800, SB-700, and SB-600 (it does not have a TTL multiple flash terminal). The above is quoted from the Nikon website.