The Atlas A-Line EJW115XI-B is a single 15" passive subwoofer in an optimally designed and constructed sealed Baltic birch enclosure. This design provides even sound distribution. The EJW115XI-B is designed to be used with an EJ2003-B full range line array system. The EJW115X-B needs to be used as a part of a pair of ELIJAH systems where an EJW115AI-B can be used to provide power to the EJW115XI-B and two EJ2003I-B units.