A Phase Linear 400 amplifier. The amplifier has a brushed aluminum front plate with two cut-outs for volume unit (VU) meters. The front plate has black cursive text at the top and center that reads: [Direct Coupled Solid State Amplifier / Phase Linear / 400 / Four Hundred Watts R.M.S.]. Black print text found below the meters reads: [CHANNEL ACHANNEL B / POWER LEVEL]. The back of the amplifier is black metal with five sections created by metal pieces extending from the back of the machine. To the far proper left of the back there are four plastic dials, white, black, and red in color, in a vertical row. Underneath the dials there is a metal input and a metal output, both silver in color. On the side of the panel to the right of the dials, yellow text and diagrams that indicate the purpose of the dials and the input and output. Inside the next section to the right of the last, there is a caution message in white text. To the far proper right of the back there is a power cord at the top and a metal plate that gives the serial number, model and power information. The information reads: [Phase Linear / SERIAL NUMBER 1490 / MODEL 400 / MAX POWER IN 750 WATTS / AC VOLTS 117 50 TO 400 HZ / U.S. PATENT 3,727,148 / MADE IN U.S.A / PHASE LINEAR CORP. / LYNNWOOD, WASHINGTON]. There is a yellow and red sticker below the plate.