FretMaster supports a number of different instruments and sounds that are selected by clicking on the Instrument Selection button at the top middle of the screen. As you change instruments, the default sound for that instrument will also be selected.
FretMaster supports Guitar (6 & 7 String) Bass (4 & 5 String), Banjo (4 & 5 String), Ukulele, and Mandolin, with sounds including Electric Guitar, Overdriven Electric, Acoustic Guitar, Bass, Banjo, Ukulele, Piano, and Mandolin