Amazon.com: String Action Ruler Gauge Tool for Electric Bass and Acoustic Guitar : Musical Instruments
Guitar String Action Gauge Set Up Ruler for Electric, Acoustic, Bass, Classical Guitar – Imperial and Metric Measurements – 500 Micron Anodised Steel – MADE IN UK – BigaMart
String Spacing Ruler
LT-4252-000 String Action Ruler
String Action Gauge - Guitar Pocket Multi Tool - multi spanner wrench, ruler - Philadelphia Luthier Tools & Supplies, LLC
Amazon.com: Alnicov Stainless Steel String Action Ruler Guitar Setup Gauge Luthier Measuring Tool with User Guide for Electric, Acoustic & Bass Guitars : Musical Instruments
Amazon.com: String Action Ruler Gauge,Guitar Repairing Tool for Luthier,Fit for Guitar,Ukulele,Bass,Banjo,Mandolin : Musical Instruments
Amazon.com: StewMac String Action Gauge And Ruler, Metric, Stainless Steel - Designed by StewMac, The Original measuring tool for acoustic and electric guitar, and bass setup : Musical Instruments