Sealife DIGITAL FLASH Instruction Manual page 16

Pre-flash cancellation settings:
The Pre-Flash cancellation switch setting matches the number of pre-
flashes of your camera:
Switch position
0
1
2
3
4
14
Description of setting
Instant synchronization mode.
For cameras with No pre-flash.
Use "0" setting for all SeaLife cameras an
other brands that allow you to disable the
camera's pre-flash.
One pre-flash
Two pre-flashes
Three pre-flashes
Four pre-flashes