Designed for use with the DA-250DH, DA-250FH, DA-500F-HL and DA-500FH Multi-Channel Power Amplifiers, the MT-251H electrically isolates the high-impedance speaker lines from the amplifier. The DA Series multi-channel digital power amplifiers are ideal for multi-zone distributed speaker systems and professional sound applications. Engineered with Class D technology, the new DA Series amplifiers operate at 85 percent efficiency and consume almost one-third less power than conventional analog amplifiers. The compact and lightweight single or dual rack-space design and ultra-low heat dissipation allow designers to rack-mount up to five units without open space between units.