down instrument. [ edit ] Construction Legend: 1. Headstock : 1.1 machine heads ; 1.2 truss rod cover; 1.3 string guide; 1.4 nut . 2. Neck : 2.1 fretboard ; 2.2 inlay fret markers; 2.3 frets ; 2.4 neck joint. 3. Body; 3.1 "neck" pickup ; 3.2 "bridge" pickup; 3.3 saddles;