This Polk Audio 5.1 Home Theater Speaker bundle includes:TSi400 4-Way Tower Speaker with Three 5-1/4 Drivers - Pair (Black) TSi100 2-Way Bookshelf Speaker with 5-1/4 Driver - Pair (Black) CS10 Center Channel Speaker with Dual 5-1/4 Drivers - Each (Black) PSW108 10 Subwoofer (Black)  TSi400 Tower SpeakersStep down in size from the TSi flagship TSi500 when you want big impact in a smaller room. Here, three smaller drivers in the classic TSi narrow baffle design make more efficient use of power, while delivering the same wide, realistic soundstage and deep, musical bass response you desire.Features:Unlike other speakers in this price range, TSi enclosures are constructed of extensively braced, solid MDF with 3/4-inch baffles. This virtually eliminates internal resonances and damps energy-stealing vibrations, for more efficient operation and more transparent sound. Polks proprietary, patented Dynamic Balance technology allows the engineers to design out distortion-causing driver and system