Kangnice Set of 9pcs Guitar Understring Steel Radius Gauges for Luthier Tools Bridge Pin Understring radius gauge,7.25, 9.5, 10, 12, 14, 15, 16, 17 and 20 radii Laser cut from stainless steel ,Etched with radius on handle (1mm) thick ,(1mm) thick  (67mm) wide These come in the most popular fingerboard radius and make it easy to measure the radius from either above or below the strings. Use these to accurately setup your guitar bridge saddles to match the fingerboard radius. Quantity:1Set(9pcs,Not include the guitar )