This fitting screws in the top of the power steering pump and is a required update for the 944.347.445.05 supply hose.
See also:
944.347.445.KIT Update Parts Kit
Fits:
924S 86-88
944 83-90
944Turbo 86-90
944S 87-88
944S2 89-91
968 92-95
Reference/Interchange Numbers
99923035702
999.230.357.02