Read the Performance Auto & Sound review of the GTA-400M

PERFORMANCE
• High efficiency Class AB design
• Boston’s Q-Tune™ circuitry for Simple Bass Output Optimization
• SST™ (Symmetrical Signal Topology) system uses balanced asymmetrical inputs
for noise cancellation
• Fully adjustable and selectable Lowpass/Highpass crossovers
• Wrap-around heatsink design for ample cooling in multiple mounting positions

INSTALLATION
• Compact chassis allows for placement flexibility
• Dedicated High- (speaker level) and Low- (RCA) level inputs
• Optimal angled speaker and power blocks for easy wire connections
• All input/output connections are located on one side of the amplifier to ease installation
and wire management
• IMS™ (Integral Mounting System) reduces the amplifier footprint
• Recessed control panel for clean installation and concealed wire management
• Optional GTA-RSL remote gain for controlling the subwoofer volume from the drivers seat

Number Of Channels:
4 Channels
4 Ch. Power @ 4-ohm (CEA-2006-A):
50 Watts x 4
4 Ch. Power @ 2-ohm (CEA-2006-A):
80 Watts x 4
Mono Power @ 4-ohm(CEA-2006-A):
160 Watts x 2
Frequency Response (-3dB):
10Hz-50kHz
Signal to Noise Ratio (A Weighted):
>90dB
Lowpass Crossover:
12dB Adj. (50Hz to 200Hz)
Highpass Crossover:
12dB Adj. (50Hz to 200Hz) 
Height:
2 3/8"(61mm)
Width:
14 3/4" (375mm)
Depth:
8 3/8" (211mm)