This AS-10 TTL Multi-Flash Adapter can connect up to 3 additional TTL Speedlight with SC-18, SC-19, SC-26 or SC-27 TTL sync cord This AS-10 TTL Multi-Flash Adapter can connect up to 3 additional TTL Speedlight units with SC-18 , SC-19, SC-26 or SC-27 Multi-Flash sync cords. The adaptor can controls up to three TTL speedlight flash units simultaneously.