Googled this:
Date Added: 31st August 2007
Question: What do I need to use this flash with my olympus 5050 zoom with underwater case
Bristol Cameras Answer: As well as the strobe you would need a tray and arm, a good set up would be the 10Bar single stay slot tray and the 36cm 10Bar flexible arm. If you want to trigger the strobe via a fibre optic cable (rather than relying on the slave sensor) you would have to also purchase the Sea & Sea fibre optic cable (50107) and the Strobe Mask set. Hope this is of help to you.
This was from an English outfit, Bristol Camera. The UFL-1 is a slave strobe. It mimics the Olympus built in flash. They say it can be used without a fiber optic cord, but from my experience-not a good idea. In bright light, you often don't get response from a slave flash, or it fires due to sunlight. Also, without masking the built in flash, you'll tend to get backscatter, i.e. light reflected back into the lens by particles in the water because the flash is too close to the lens. With a fiberoptic cable, you can mask off the flash and just use it as a signal to the strobe, which is held much farther from the lens and aimed slightly away from the subject, so just the edge of the light covers the subject and less light is reflected back.