Bluelans&reg; Double Sided Multi Function String Action Guitar Set Up Gauge Ruler User Guide Luthier Measuring Tool for Electric, Acoustic Bass Guitars Measures: String height, Pickup Height, Bridge saddle height, Saddle slot depth, Fret slot depth(unbound fingerboards), Nuts saddles and polepieces Made of durable Stainless Steel with etched printing which will never wear off. Features a string action setup guide. Perfect for setting up your guitar to suit your personal taste. Easy to use whether you are doing your first guitar setup or are a professional luthier. With user guide sheet. Free plastic holder ~ Very Accurate and Clear. Simple and easy to use. Also suitable for other stringed Instruments. Size: 89mm/3.5" x 51mm/2.0"(Approx.)