Zapco ST-4X II 360 Watts 4-Channel Class A/B ST-X Series Amplifier The Zapco ST-4X II 360 Watts 4-Channel Class A/B ST-X Series Amplifier was designed specifically for today's car audio market The square, low profile chassis also means it will be easy to trim out for a great looking installation so your system will look as awesome as it sounds. Pass this amplifier from car to car, and down generation to generation as these amps are built to last Class A/B, ST-X Series Amplifier Dimensions in mm: 160(W) x 52(H) x 260(L) Overall: 160(W) x 52(H) x 302(L)