Sunpak PZ42X TTL Shoe Mount Flash (Sony) PZ42X runs on 4-AA batteries in a compact and light body: The recycle time is about 3.5 seconds. The photographer can seize opportunities to shoot precious moments, for example, at wedding ceremonies, parties and athletic meetings To realize the maximum Guide Number 42 (ISO100-m): This covers well the illumination area with a focal length of 100 mm (when converted to 35-mm film size), which is considered to be most suitable for portrait shooting (Up to 21 m) Compatible with TTL functions of digital SLR cameras: Compatible with the advanced flash output control function for Sony ADI Flexible bounce function: The light emission part can be moved 90 deg. upward, 180 deg. to the left and 120 deg. to the right, flexibly responding to every possible bounce shooting situation EV adjustment function: The photographer's intention can be freely represented by the EV adjustment function up to +/-1.5EV