A combination of advanced technology, extensive research and rigorous testing, Bose 251 speakers set a new standard for performance and reliability outdoors. An Articulated Array speaker design reproduces sound over a larger listening area. The result is a wide distribution of sound, so you can enjoy music equally from both speakers as you move around outdoors. And the patented multi-chamber enclosure helps reproduce music’s lower reaches with exceptional fullness and depth, without audible distortion, from a small design.