About the product: 1. The revolutionary new tool fretbar understring leveler lets you level your frets under full tension without removing the strings. You can level your frets with the strings ON. 2. Material: Aluminum - CNC machined. High glossiness, durable and long-lasting use, not easy to deform. 3. Applicable for fret, saddle, and fingerboard sanding, great accessory for players and luthiers. Suitable for the fret leveling of electric guitar, acoustic guitar, electric bass, banjo, mandolin, etc. 4. Made of top grade Aluminium, CNC machined with nice oxidation blasting treatment. 5. Used with the strings on or off, the precision-ground surface works quickly and accurately to get frets level. 9inch length (228mm) is designed for smaller necks like ukuleles and mandolins. It also works for leveling full scale necks and spot leveling. Material: Aluminum alloy Length: 228mm/9in Color: Black Package Contents: 1 x Guitar String Straightener Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.