BEL AVENIR 4 Pack Curtain Tiebacks Handmade Decorative Curtain Holdbacks Rope with Tassel- Brown

How do they not slide down, Can they stop perfectly on the curtain?

How wide is the rope? What is the diameter, 1/4"?

Which of your ties have a 1.6 diameter thick rope I want

Is the navy a true navy? I recently purchased a different tieback which was supposedly navy but was actually turquoise.