Hey, I'm currently traveling (testing the new hiking pants on a 2 week trekking tour) and have bad reception here, otherwise I'd find the link for you. The fabric is from extremtextil.de, search for bike jersey. It came quite cheap at 14€/m. But it was a challenge to work with. You have to be very careful when laying out the fabric for cutting, as it easily stretches even when just lying on the table (and then you've cut the wrong size 😵‍💫)