Curv-O-Mark style Wrap-A-Round rulers are an easy-to-use tool for pipe fitters and welders. Each is printed with a scale in inches, an inch chart, a tangent chart, and other helpful markings to help make a straight line around pipes. Made from flexible gasket material, they have good resistance to both heat and cold. B material has a service temperature of up to 175°c (350°f). GG material is used for high-temperature applications up to 280°c (550°f).