The Bose AV3-2-1 Series I/II/III 3-2-1 Acoustimass Sub PS321 Power Cord 321 is a wired power cord designed specifically for the Bose AV321 model. It is compatible with Series I and is a unit quantity of 1, making it a single cord that can power the Acoustimass Subwoofer in a home theater system. The power cord ensures easy connectivity and reliable power supply for optimal performance of the Bose AV321 speakers.