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. It's easy to use even on your first dive! By turning on the pilot light you can see accurately how the image will appear before you press the shutter button. This way you can quickly find the right position for your LSD and start shooting. TECH SPEC: aluminium anodized housing weight: 600g body length: 215mm depth rating: -80m focal length (in water) ≈ 175mm focused light beam diameter (in water) ≈ 60mm 6 standard shapes included The package includes: LSD Ultimate with mount for strobe of choice (please select from drop-down list) Standard mask set