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) shape for their fret markers to create a brand identity set themselves apart from competitors. Gibson uses isosceles trapezoids while Fender uses dots, but others include lightning bolts, letters and numbers. Smaller dots are also usually inlaid into the upper edge of the fretboard or the neck so as to be more visible to the player who views the instrument from the side. LEDs or optical fiber can be employed to illuminate the markers. This is mostly employed by players who perform in front of live audiences where the lighting is either insufficient or constantly changing. On guitars, there are