Ged is the "rotating" bit like a ceramic bullet. They don't actually rotate the just osilate like the loose end of a high pressure hose does, within the brass housing
The actual nozzle is very small one eight bsp and is inside the ceramic bullet you just pull the top off the bullet and unscrew the nozzle. Whwe I say just...... it's not easy as it's so small. Once again the nozzle has to match your flow and pressure (nozzles have a coloured spot on em)
When yur'e reassembling it there is usually a rubber buffer on the bullet you have to adjust to make the nozzle "wobble"