Breakaway fittings: type & placement

[1carwash1]

Where should the breakaway fittings be installed? At the inlet to the high pressure gun or at the end of the high pressure boom or both?
Also , there are several types to choose from, Suttner, Mosmatic, etc. Any recommendations?
Thanks

 

[MudMoney]

I install one break away fitting on nipple @ boom,then a 12" inch flex hose with swivel to hp wash hose then a sw504 swivel @ gun. Break away is a J.E. Adams

 

[ShinePro]

Mine are on the inlet of the high pressure gun.