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.
Just look up cable for your specific model. Sennheiser hdXXXX cable. On eBay, Amazon, AliExpress etc.