The Sela Kalimba 17 Hollow has a hollow body made of fine Koa wood. Koa is a rare type of acacia that only grows in Hawaii and is often used to build instruments due to its balanced sound. Like a guitar or ukulele, the hollow body with resonance hole provides a powerful sound. This model also has a pickup, which allows the Kalimba to be connected to a PA system for live performances or to a recording device for recordings.