The S2 is an ultra-compact speaker that lets you put Polk"s widely respected signature sound in any room of your home. The S2 comes with both black and white swappable grilles for supreme flexibility, and can sit horizontally or stand up to fit in small spaces like bathroom countertops. The speaker uses two 2" (50mm) full-range drivers powered by a two-channel amplifier, while the two passive radiators create fuller bass response.