Nissin Di866 Speedlight for Nikon Digital SLR Cameras, Guide number 198 Guide Number (ISO100): 60m, 198ft. (105mm), 40m, 132ft. (35mm), Focal length Coverage: 24105mm (18mm with wide angle diffuser) Flash Duration: Manual mode 1/300 (Full Power), TTL mode 1/300-1/30000 sec., Stand-by mode: 30 sec., Display screen switch off Color Temperature: 5600K Rear curtain sync., High speed sync., Red eye reduction mode for Nikon, Slow sync. mode for Nikon, Red eye reduction mode, Slow sync. mode for Nikon Power Source: 4 x AA battery, Recycle Time: 0.1-5.5 sec. (Alkaline, NiMH), Number of Flashes: 150-1500 times