changing bathroom Tap

[Sargis Petrosyan]

I want to change my bathroom sink and the new tap pipe does not match with old pipes and I am not sure what I need hear some adapter?
my new tap pipe dimension is 16.5(3/8) mm

 

[Testarn]

It looks like there is a coupling between the water pipes and the current tap. I'd remove that and bring it and the new tap to a shop where they can help you find a new coupling(nippel) with external threads that matches the old pipes and an external thread that fits the new tap.

Then you can connect the old pipes with the new tap.