Need a help with picking a conductive and stretchable fabric/cord/yarn for breathing sensor

I want to make a breathing rate sensor with a chest belt. The idea is that when you breathe, the belt stretches and I want to measure that to count breaths. I was looking for kind of conductive and stretchable fabric/material that simply changes its resistance with stretching. I found suitable products on digikey.dk but rn they are sold out: https://www.digikey.dk/da/products/detail/adafruit-industries-llc/1167/6563021

I also found a conductive fabric, but I’m not sure if they are stretchable enough: https://www.digikey.dk/da/products/detail/adafruit-industries-llc/1364/8558265
Can you help me with finding the right product that is available on Danish site?