The Tannoy iw4 DC is a full bandwidth in wall speaker system, using a 100mm (4″) Tannoy Dual Concentric™ point source, constant directivity drive unit, designed for installation into standard stud partition wall systems. It may also be used in cavity wall installations constructed with standard thickness drywall as well as a wide range of other wall construction types with a surface thickness of up to 25mm (1”).