O-Ring size for S14 P/S line-to-rack

[teddyjr]

Putting my lines back on today and discovered the o-ring is missing off the end of the line (the one with the banjo end and pressure switch in it). I don't want to wait to order one and was hoping someone could vernier one for me. It looks like it might be 6.5mm ID with a 2mm CS (cross section). I have an assortment but it looks like more than one might work and I'd like to put this together once.

Thanks in advance.