1. TD-383 is a power pack for Nikon flashgun 2. TD-383 uses a dual circuit charging system. Charging time is much fast than any other battery pack. 3. Convenient design; you can either use 4 or 8 AA batteries. It will be faster recharged when using 8 AA batteries. 4. TD-383 uses a new charging method, its almost no power consumption under the stand-by mode. 5. Compatible Flash: Nikon SB-800, SB-80DX, SB-28DX, SB-28, SB-27, SB-26, SB-25, SB-24, SB-22, SB-20, SB-11