Good way to double the flash output of an internal flash.
Used as an optical slave speedlight, attached to the camera tripod connector with the supplied bracket, this flash fires when the internal flash fires. Using it with my Nikon 1 J1 camera I set it the toggle switches to S3 and Slave on. It's a great inexpensive way to roughly double the flash output. To really pump up the flash I bought a used Nikon SB26 speedlight for about $100, and use it with the same bracket. If you need an optical slave speedlight with many times more flash output, I think the SB26 is the best bang for the dollar.