The guide number is 328 as per the model designation. It bounces, zooms and swivels. The flash comes complete with a bracket. This unit is compatible with all digital cameras with either built-in flash capability or not. It has a hot shoe so that it can be fired from the camera too. It is fully synchronized with fill-in flash and red-eye reduction flash and can be used with virtually all of the digital cameras on the market. It works as a slave. It can be set for a single flash camera or a pre-flash camera, or, it can detect which setting is best. Off-camera flash refers to setups where the flash is not directly attached to the camera's hot-shoe. The benefits of such a setup is that the lens-flash distance can be greater, and thus more natural look can be achieved, the probability of red eyes is reduced, and more than one flash units can be used. In this document I will briefly cover three of the most common methods for operating flash units off-camera. Ordinary flash units will not work because your digital camera lacks a way to connect and/or mount an external flash. Even more importantly, most digital cameras emit a ?pre- flash? and/or a ?red-eye? pulse that fire before the shutter opens, then an additional flash pulse is fired to actually light your picture. This ?pre-flash? (?double-flash?) and/or ?red-eye? pulse confuses other flash and slave units , causing them to go off at the wrong time, and are useless for your digital camera. The Slave Flash has special digital pulse counting slave circuitry that is not fooled by the ?pre-flash? and eliminates the need for an electrical connection to your camera. A three-position switch sets the flash to ignore one or two ?pre-flashes?, or none at all.