The D18E-AD is a very high output INFRA subwoofer system designed to provide high fidelity extended low frequency audio reproduction from a relatively small and low-profile enclosure. The D18E-AD provides perfectly flat response down to 8 Hertz when used in conjunction with the 8 Hertz Infra Integrator. Designed for permanent installation, the D18E-AD offers a total height of 15" enabling it to fit under platforms and in tight vertical spaces. Standard features include a durable flat black painted finish and a black coated steel grille.