A fret and fret board assembly for a stringed instrument provide increased fret stability and serve to increase the duration of fretted notes played on the instrument. Each fret includes a string-engageable cap, a relatively high-mass tang or resonation bar which fits snugly within a mating groove in the fret board and a pair of wings which extend outwardly in opposite directions from the cap and tang and engage the fret board to provide additional stability to the fret and further add to the mass of the fret. The tang preferably has a relatively large outer perimeter so that the interface between the fret board and each of the tang and wings is generally increased. The tang is preferably configured for installation and removal by sliding the fret lengthwise in and out of the groove. The fret board may include reinforcing rods.