FOXNOVO 6-in-1 Nut Files Stainless Steel Ruler Winder Guitar Luthier Repair Tools in A Packet Material: durable stainless steel and hard plastic. File length: Approx. 19.5cm 7.7 inch. Three double-edge nut files, with 6 different specs, the set of tree files does the work of six, available for acoustic guitar One stainless steel ruler, used at the bottom while nut slotting, act as the nut slotting depth benchmark, also to prevent scratches finish A sheet of string action ruler with centimeter and inches unit on side, can quickly find the right distance and measure the accurate string height One special patent string winder, available for manual or fixed at electric tolls to operate.