I seem to have a couple of these for some reason. I've never had a 128 but i did have an X1/9.
not sure if they came from an 850 but who knows, The pair i have are still flexible but could do with a clean up, they are 40mm wide by 60mm long as your photo.
I think you have my email address already, saves me from posting it here.
I am in high wycombe if your passing or i could send them
