Fiber-connector DS is for synchronization firmly between digital camera housing and ES series of digital strobe.
ESA stay & arm series are equipment for digital underwater photography to set up accessories which is trobe,light,lens and so on.
You can choose the each parts as you like.
Type-S(Length 440mm)

Type-L(Length 570mm)

for ES-230 DS
for ES-150 DS
Diffuser-cap for ES-150 DS Alfa
Diffuser-cap for ES-230 DS Auto