Carbon fiber is one of the hottest materials out there! Race car enthusiasts know this well! Known for it's strength with its extreme lightweight, many view it as an alternative to titanium. These are a great addition for any men's or women's collection. These are an exceptional complement to blue, white, and many other french cuff shirts. Each pair is finished by hand to ensure a quality, lasting pair. We are the only sellers of our one-of-a-kind designs so you are sure to stand out from the crowd. They measure approximately 5/8" in diameter.