The fret wire on the revolutionary Robot SG Special Limited is a combination nickel and silver alloy (approximately 80 percent nickel and 20 percent silver) specifically designed for long life and superior wear. Gibson’s traditional “medium/jumbo” fret wire is first shaped by hand, then cut to an exact 12-inch radius. After hand pressing it into the fingerboard, a machine press finishes the job to eliminate the gap between the bottom of the fret wire and the fingerboard.