When the YS-D3 is fired at Guide Number over 22, a two-stage ready-to-fire signals will be issued. For instance, after the strobe fires at full power of GN33, the strobe will inform you both visually and audibly when the condenser is charged to fire at GN22. Then, when the condenser is charged enough to fire at GN33, another different signal will be issued. This design allows you to release more shutters in scenes where you want to shoot as many pictures as possible, maximizing shooting intervals between scenes. Incorporating a uniquely designed aluminium heat diffuser, the target light is now powerful enough to be used as a dive light.（About 4 times brighter than YS-D2）. Backlight panel that is effective when shooting in dark environments The indicator color on the back of the YS-D3 changes each time the position of the mode switch is changed. Blue (in DS-TTLII mode), light blue (in slave TTL mode), orange (in manual mode with pre-flash), and green (in manual mode without pre-flash) The positioning of the operation system is obvious during night diving. The YS-D3 comes with a straight type ball base.