Russian guitar usually differs from the wood in the rest of the neck. The neck joint or heel is the point at which the neck is attached to the body of the guitar. The fingerboard is made of hardwood (ebony or rosewood are common), fitted with metal frets of brass or steel. Fret spacing almost always follows the western twelve tone equal temperament (12-tet) system. The surface of the fingerboard may be flat or curved slightly ("radiused"), although the curve on the Russian guitar is usually somewhat less than that of an equivalent western 6-string guitar. Inlayed position markers are common, and
Inlay (guitar) Inlay (guitar) Inlay on guitars or similar fretted instruments are decorative materials set into the wooden surface of the instrument using standard inlay techniques. Although inlay can be done on any part of a guitar, it is most commonly found on the fretboard, headstock —typically the manufacturer's logo— and around the sound hole of acoustic guitars. Only the positional markers on the fretboard or side of neck and the rosette around the sound hole serve any function other than decoration (the rosette serves as reinforcement). Nacre ("mother of pearl"), plastic and wood are the materials most often used as inlay.