Standard Contour Marker, Compatible Pipe Diameter (Maximum) 18 in, Compatible Pipe Diameter (Minimum) 1 1/2 in, Includes Soapstone Crayon, Display Units of Measure Degree, Inch, Features Calibrated Protractor, Triple-Jointed Marking Arm, X-Shaped Frame, For Use On Structural Steel Members, Tool Material Steel, Tool Type Curv-O-Mark Marker