The Nissin Di866 Mark II Flash Unit (Nikon i-TTL) features outstanding functions and professional performance with a guide number of 60 and sub-flash with a guide number of 12. Additional features include a convenient color display with rotation sensor, external service port for firmware updates, wireless TTL system support, auto zoom, external power pack socket, x-terminal socket for flash syncronization, rear curtain sync, built-in reflector and diffuser panel, and a 90° tilting / 180° rotating flash head.