Which system does this piece belong to?

[petrk]

Hi,
this ring came with Rodagon 90mm enlarging lens which I bought recently. It is cca 2,5cm long. Can someone help me with identifying the enlager system which the ring belong to? Thank you much!

Regards

Petr

 

[ic-racer]

Commercial printing equipment?

 

[petrk]

Thank you, ic-racer.