the sssnake Optical Cable 15m

If I run out of channels in a project recording situation I can use this cable to run an ADAT interface as a digital multicore (it has saved the day on more than one occasion...)

It's a thicker, more rubberised cable than most optical cables i've used, and seems to be a lot more durable (important over this distance). the only disadvantage is that the heavier metal connectors are tend to wobble out more easily than their flimsy plastic brethren.