Sundown Audio SDX-100.4 4-Channel Class D Amplifier, 135W x 4 RMS, Weatherproof

The Sundown Audio SDX- 100.4 is a compact 4-channel weatherproof Class D amplifier made for car, UTV, powersports, and open-air vehicle audio systems. Its water-resistant design helps keep the amp ready for changing conditions while giving your setup clean multi-channel power. This amplifier delivers flexible RMS output for different speaker layouts, including 135 x 4 at 2 ohms, 100 x 4 at 4 ohms, and 270 x 2 at 4 ohms bridged. A sealed control area and removable cover keep the tuning section protected, and the badge can be removed with an allen key to access audio settings.

Built-in tuning controls give installers room to shape the system with variable 12dB high-pass filters, low-pass filters, x1/x20 crossover frequency multipliers, and variable bass boost at 50Hz. DC auto-sensing turn on and protection circuitry help support dependable daily use.
Technical Highlights: Amplifier
Type: 4-channel weatherproof Class D car audio ampPower
Output: 135 x 4 at 2 ohms RMS, 100 x 4 at 4 ohms RMS, 270 x 2 bridgedVoltage
And Fuse: 11.5V to 15V operation with 50A recommended fuseSize: 8.875 x 7 x 2.125 in with heavy cast aluminum heat sinkControls: Removable audio control cover with optional wired remote controlThis SDX- 100.4 amp is suited for car stereo builds, UTV systems, powersports audio, and open-air vehicles where space, tuning control, and weatherproof construction matter. Its compact aluminum housing, water-resistant build, and detailed crossover options set it apart for installations that need power and practical system control.