YSTD&reg; Electric Guitar Bass String Action Guide Setup Measuring Luthier Gauge Ruler Can be used to measure:String height/Bridge saddle height/Saddle slot depth/Fret slot depth (unbound fingerboards)/Nut height/Pickup pole piece height. Pay this one gauge, saving you the cost of two seperate gauges Faster and more accurate than using a ruler Quality: Made of durable Stainless Steel ,Convenient , compact credit-card sized rule SizeApprox 87x51mm