What is this blow nozzle?

[Mick56]

Got this blow nozzle with some other old tools at a sale. Any idea what it could be for? I blew some air into the pipe, and the air came out whether I squeezed the lever or not

 

[Roberts210]

Looks to me like it might be for water instead of air.

 

[RTM]

Radiator filler, or sink for commercial dish washing?

 

[powerwagon63]

Part of a Hudson sprayer, missing the wand etc.

 

[powerwagon63]

 

[Provincial]

Hudson sprayer tip but set up for close work. The nozzle is designed for a fog spray, and probably was originally mounted on the end of a wand (extension pipe between the valve and the nozzle head).