1String action gauge ruler is made of stable, durable and beautiful PVC material 2Unlike the guitar string height ruler made of stainless steel or other metal materials, this string action gauge ruler is soft and not easy to scratch 3The product is a practical guitar or bass measuring ruler, compact and light, easy to use 4This gauge is suitable for electric guitar, bass, folk guitar, mandolin, banjo, etc. 5The scale is clear and not easy to fade, which is convenient for you to view and read, very useful and helpful