Boston Acoustics GT-2200 900W RMS, GT Reference Series 2-Channel Amplifier (GT2-200) GT Reference Series 2-Channel Amplifier 4 ohms: 200 watts x 2 chan. | 2 ohms: 350 watts x 2 chan. Frequency response: 10-95,000 Hz Q-Tune technology combines sophisticated crossover adjustments with Q-Control settings to seamlessly transition rear bass to the front sound stage Dimensions: 18-3/4"L x 9"W x 2-3/8"H