StewMac understring radius gauges SM2309

Understring radius gauges, standard width, set of 4 Fast, accurate bridge saddle adjustment! Each of these unique gauges has an accurately radiused arc on both the top and bottom surfaces, and is shaped to fit easily under the strings. Use the bottom curvature to determine your fretboard radius, and the matching top curvature becomes a reference for setting string saddle heights for best playability. The slim shape of these stainless steel understring gauges allows you to read the fretboard radius even with the strings on! This is also handy for matching pickup polepiece heights to the arc of the strings. And setting bridge saddles is easier than ever. This standard-width set covers 6-string guitars and most 4-string basses. The gauges span string spreads up to 2-5/8" (66.68mm). It includes the four most common radii: 7-1/4", 9-1/2", 12", and 16".