For accurate fretting and neck evaluation. We make our Precision Straightedges specifically for checking neck straightness and relief, evaluating truss rod adjustments, and pinpointing high or low frets. The narrow beveled edge allows easy and accurate viewing of the gap between the edge and the surface being checked. Made of durable stainless steel with a satin finish for easy marking with a pencil, each straightedge is precision-machined for accuracy to ±.0015" per foot. This 18" straightedge is ideal for use on electric and acoustic guitars, but also works on bass guitars. This straightedge is also ideal for laying out projects on wood or paper, and for setting up table saws, jointers and other shop equipment. Made from surgical stainless steel, hardened and tempered for lasting accuracy.