and 1940s, tenor guitars became much less played, although some tenor guitar models had been made in very large numbers throughout this period and are now still common. Tenor guitars came to prominence again in the 1950s and 1960s, possibly due to the effects of the Dixieland jazz revival and the folk music boom. At this time, they were made by makers such as Epiphone, Gibson, Guild and Gretsch as archtop acoustics and/or electrics, as well as a range of flat top models by Martin. Around this time in the 1950s and 1960s, electric tenor guitars were also referred to as "lead guitars", although the rationale for this is not now clear, unless it was for marketing purposes. Lead playing on a six-string guitar often involves just using its top four strings. A major player of the electric tenor as a lead guitarist in the bebop and rhythm and blues styles from the 1940s to the 1970s was the jazz guitarist Tiny Grimes, who recorded with Cats and The Fiddle, Charlie Parker, Art Tatum and others. Tiny used guitar (DGBE) tuning on his tenor guitars, rather than tenor CGDA tuning. The Martin 0-18T flat top acoustic tenor guitar was played in the late 1950s by Nick Reynolds of The Kingston Trio. The acoustic tenor guitar became a popular instrument in the folk music boom of this period, particularly this model. In 1997, as a tribute to the Kingston Trio, Martin re-issued 34 limited edition 40th anniversary commemorative sets (40 sets had been planned, but only 34 orders were received and executed) of the three main instruments used by the Kingston Trio to celebrate their founding in 1957. The commemorative set included a custom Martin Kingston Trio KT-18T tenor guitar with "The Kingston Trio" and "1957–1997" engraved on the fingerboard in mother-of-pearl and its label was signed by C.F. Martin IV, the CEO of Martin Guitars and four of the surviving members of the Kingston Trio. Current use Since 2001, there has been an increased interest in the tenor guitar, as evidenced by an increasing number of manufacturers, such as Eastwood Guitars, Blueridge, Gold Tone, Artist Guitars, Canora, Thomann, Harley Benton and Ibanez, offering tenor guitar models, and a greater number of specialist luthiers now building custom tenor guitar models or offering to modify existing instruments into tenor guitars. Kala recently introduced a 21.5″ scale acoustic tenor guitar, the KA-GTR. Contemporary