Gibson's last innovation in archtop design was the creation, in 1955, of "thinline" models with a reduced body depth. Notable thinline models include the successful Gibson ES-335, introduced in 1958, as well as the Epiphone Casino, introduced after Epiphone was acquired in 1957 by CMI, Gibson's parent company. These were more feedback resistant, comfortable to hold and easier to play standing up. The first thinlines were hollow bodies. Later thinlines such as the ES-335, ES-345 and ES-355 were semi-hollow. Thinlines can be classed as semiacoustic guitars, although not all semiacoustic guitars have an arched top. Thinlines became popular with mainstream pop and rock artists during the 1960s. The ES-335 and similar guitars were taken up by, and remain steadfastly popular with, electric blues players; B B King's various "Lucilles" are based on the ES-335.