Other companies don't care, but we care,  a sealing leakage can be very dangerous, a leakage can work like a nozzle.
We worked out the exact dimensions of the copper ring to get the right sealing
All our 1000 bar (15K) nozzles / adapters do have flat facing seal ends for copper washer sealing.
All our prices of the nozzles / adapters that required copper washer, are included copper washer.