Embrace light. Admire it. Love it. But above all, know light. Know it for all you are worth, and you will know the key to photography.
The Light Shaping Device is made for your underwater flash.
The Light Shaping Device (LSD) works like a projector which takes light from your flash and pilot light to create a beam with a sharp image at the focus distance. The LSD uses elements like a lens, mask and a diffuser to generate the light beam.