Semi-hollowbody electric guitars -- also known as thinline guitars -- often look like hollowbodies from the outside but contain some degree of solid contruction in the body. In the case of the iconic Gibson ES-335TD (easily the most recognizable model in this class), a block of wood runs through the center of the body between two hollow cavities on the top and bottom. Compared to full hollowbody designs, these guitars tend to feedback less and offer arguably more sustain in their sound. Other classic examples include thinline Telecaster models from Fender as well as many of Rickenbacker's iconic designs like the fab 360-12, not to mention an entire genre of Gibson ES-335 imitators.