Adjustable Trammels used in marking over large distances, tracing contours and scribing circles. The 6" scribing points are adjustable, and can also be replaced with pencils, pens, crayons and soapstone for marking various surfaces. The heavy-duty clamps will fit 5/8" to 1-1/2" beams of any length. Set includes: (2) two trammels and (2) two 6" scriber points.