Line etched into metal union

[anastasia.edsell]

What does it mean when a metal zero dead volume fitting has a line etched into one side of it around the outer rim? Does it mean its a dual internal diameter fitting?

[Peter Apps]

Could be, metric swageloks have a shoulder machined onto the hex flats. Your best source of information is the manufacturer of the connector.

[James_Ball]

Also make sure the threads are not reversed on the connection. Sometimes a line cut into a nut or fitting indicates reversed threads.

[Consumer Products Guy]

Could that designate a bored-through union??

[anastasia.edsell]

I asked an Agilent technician (the manufacturer) this morning who stopped by and he said that means its a union that is suitable for bio-inert applications.

Thanks for the replies everyone!