Di622 Mark II has a wireless remote flash system as a slave unit. You can enjoy creative flash photography with multiple lightings from the various directions. There are 3 slave modes provided. Slave Digital (SD): Di622 Mark II synchronizes to the pre-flash system. The master flash is to be set at TTL (E-TTL for Canon and i-TTL for Nikon) mode. Slave Film (SF): Di622 Mark II synchronizes to the traditional single flash system. The master flash is to be set at manual mode. Studio lighting system synchronizes to this mode. This mode is also available for open flash, and for a standard flash in the market. Wireless TTL: Di622 Mark II synchronizes to the wireless remote flash system. The master flash is to be set at Channel 1 group A in wireless remote mode. Nissin Original "MY TTL" Setting The pre-set value is memorized as your personal standard after switching the unit off. The usual TTL flash level compensation works based on this customized level. X-Contact and External Synchro Contact Di622 Mark II can be used without hotshoe cameras. Some cameras provide a flash synchronization contact at X-terminal instead of hotshoe. For this type of cameras, Di622 Mark II has a X-terminal socket for flash synchronization.