This is the cable for my Sennheiser headphones. does is have a particular name??? Mine isn't working properly and I've been trying so hard to find a new one to buy but nothing comes up in my country with just searching for it. I don't know what the thinner part is called.
I believe it is a cable with one end being 3.5mm and the other being 2.5mm. you can search for that or a sennheiser momentum replacement cable.