OM 606 Fuel Line O-Ring Spec - Anyone Know The Size/Type?

[nhdoc]

My fuel lines are less the 2 years old but since i have just developed a leak at the delivery valves I will be pulling the intake manifold off to replace them and thought it would make sense to at least explore the possibility of replacing the o-rings on the plastic fuel lines while I am in there.

The lines themselves are probably OK since, as I said they were replaced early in 2005 but I would like the extra confidence of knowing the o-rings are renewed.

Here's my question - does anyone know the size/spec for those rings? MB only sells the lines with the fittings pre-ringed but I assume the o-rings are just a stock item...anyone got any ideas?