The SB-700 Speedlight Shoe Mount Flash from Nikon is an on-camera flash, designed for use with Nikon DSLR cameras that use the i-TTL metering system. It is compatible with DX and FX sensors, and its power zoom head covers a 24-120mm range when used with an FX camera.
You'll be able to use the strobe directly on your camera via the hot shoe, or wirelessly as a Commander or Remote. Using the flash as a Commander allows you it to take control over other Nikon Speedlights.
As a Remote, it can be controlled by another Speedlight, or your camera's built-in flash. Its Quick Wireless Mode, with A:B light ratios, allows you to quickly adjust settings on multiple flash units -- giving you the ability to control two remote units in i-TTL mode.