Pre-slotted with string location grooves to make spacing and positioning a when performing the last string slot filing. You can control the height of each string with raising the screws of the nut and get the string height that you need. brass and metal,it is harder than the other.Great upgrade for your old or nut. Adjustable guitar nut great for 6-string single cut electric guitars. Length: 42mm; Width: 5mm; Height: 2mm; E to E string 35.5mm; Please make sure the dimensions are correct for your project.