BOSE (R) Acoustimass 15 Series II Home Entertainment Speaker System - White Upgradeable to 6.1 channels Automatic Protection Circuitry - provides increased reliability without interfering with the listening experience Multi-Channel Bass Extraction & Summation - reproduces deep, impactful low notes & effects for the front & surround channels from a single Acoustimass module, eliminating the need for multiple enclosures Color - White