Features: new and 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. Material: Aluminum - CNC machined. High glossiness, durable and long-lasting use, not easy to deform. Applicable for fret, saddle, and fingerboard sanding, great accessory for players and luthiers. Suitable for the fret leveling of electric guitar, acoustic guitar, electric , banjo, mandolin, etc. Made of top grade Aluminium, CNC machined with nice oxidation blasting treatment. Used with the strings on or off, the precision-ground surface works quickly and accurately to get frets level. Specifications: Material: Alloy Color: Black Type Optional: 114mm/228mm/350mm/457mm Size1: approx.457mm/18in Size2: approx.350mm/13.8in Size3: approx.228mm/9in Size4: approx.114mm/4.5in Note: Please allow 1-3mm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1Pc x Understring Leveler(Size optional)