Despite Martin's legendary status in the acoustic guitar arena, their electric guitars models have been less successful. Although in 1959 they had offered D-18 and D-28 dreadnoughts with added pickups and controls, Martin's first true electric guitars were the F series archtops introduced in 1961. These were replaced in the GT series, which was made until 1968. The GT Series consisted of three models: the GT-70, GT-75 and GT-75-12. These were semi-hollow bodied thin-line electric with two f-holes.