Men's Carbon Fiber Promise Ring - Red Black Carbon Fiber Promise Ring for Guys This ring has a step edge design and is a comfort fit band. Polished Silver. The outer band has a woven black and red carbon fiber inlay. The base metal is hypoallergenic 316L surgical stainless steel. Will not tarnish or turn your finger green. Available in sizes - 8mm - 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 Includes a black ring box. High quality and affordable.