Measurement Standard String Action Ruler Gauge With Fret Protectors Set For USEFUL SCALE:Mainly adopting stainless steel, anti-rust and durable.The gauge provides accurate measurement to string height, bridge saddle height, saddle slot depth, pickup polepiece height, fret slot depth and nut height. FRET PROTECTORS:Stainless steel fret protectors in 2 sizes are specifically designed to protect the fingerboard while working on your frets. WIDELY USE:Widely applied for string instruments, such as guitar, bass, mandolin, banjo, etc.Very practical and useful, favorite measuring tools for DIY luthiers, guitarists. MULTI USE:Pocket-sized with multi use on both side. Imperial (inches) One Side, Metric (millimetres) On The Other. With Conversion Chart of String Action at 12th Fret Printed. BEST GIFT:Best gifts for guitarist and Musicians. Great Stocking Stuffer for Birthday, Christmas, New Year, Father's day, Thanksgiving, and Holidays!