Window Blind Cord - 2.6mm Oak Blind Cord (100 Feet) Plus Threading Tool and Basic Video Instructions This product is high quality cord made for the window blind industry. High quality replacement cord made in the USA. Made of polyester fiber for high tensile strength. To reduce the chance of a return, please check how to measure the cord. With a number 2 pencil wrap the cord around 4 times. Push the cord together tight. And this should measure 1/2" when using a unworn cord. This is not exact but just a helpful tool.