Start by asking the manufacturer. We could only estimate.
Is it really DN 325? DN 300 has an outside diameter of 323.8. DN 300 and 350 seem more standard.
What flange class?
What material? (Carbon steel, stainless steel, nickel, etc.)
What size diaphragm or piston actuator, manual, gear driven, etc.?
Cast, fabricated, forged, etc.?