Washer jets.

[Oskar13]

On my Vito (639) the washer jets are mounted on the wiper arms and this works really well although they do seem to use a lot of water.

 

[Petrol Pete]

It might have been one of the French manufacturers that had the fluid pipe running up the wiper arm spraying directly on to the blade years ago, can't remember which one. My Vauxhall Omegas had just the washer nozzles heated (not much use if the hoses and bottle is frozen) . My 2006 S203 C class has electrically heated nozzles and the washer bottle is heated via pipes diverted from the engine cooling system. Seems to work well.