The SB-N5 mounts to the V camera's multi-accessory port and is powered by the camera--no batteries required. This convenient featherweight (2.5 oz/70 g) flash Compact and versatile, the Nikon 1 SB-N5 Speedlight puts creative control for flash at your command. The guide number indicates the maximum amount of flash light that the flash can produce. A higher number means that the subject can be illuminated from a Guide number (20 °C/68 °F). 8.5/27.9 (ISO 100, m/ft), 12/39.4 (ISO 200, m/ft). Effective flash range (i-TTL). 0.6m to 20m/2 ft to 66 ft (varies with ISO Electronic Construction: Automatic Insulated Gate Bipolar Transistor (IGBT) and series circuitry; Guide Number: 8.5/27.9 (ISO 100, m/ft), 12/39.4 (ISO 200, m/ft)Angle the flash up, down, left or right and bounce light to precise advantage. The flash can double as a continuous light source illuminating for six seconds Bring your subjects to life with the Nikon Speedlight SB-N5 regular flash. With a guide number of 8.5 and 12 at IS0 100 and 200 speeds respectively,