can be used in this head for example

120,-€ 

Fitting 2x male 9/16

Inside a Kiss Jet (down side) and a filter (on outer side)

see the details here for that speicial fitting

of course the hex head has an o-ring sealing

Price shown is for the metal firring (not the head) and is including nut, disk, orifice (0,0030 or 0.0025) and filter, o-rings