P-3400 Martin professional audio amplifier has air exit, power indicator, channel 1 volume control for adjustment of channel 1 input level and potentiometer for allowing adjustment of two channels at the same time. It has protection indicator when lights are on,has power switch, channel 2 volume control, channel 1 XLR input, channel 1 link socket, input sensitivity selector, operation mode selector, channel 1 turn lock output, channel 2 turn lock output, has AC cord, has air entrance, high pass filter selector, channel 2 link socket, channel 2 XLR input, has limiter selector, has crossover selector for only CA12 & CA18, bridge turn lock output for only CA12 and Ca18, has grounding selector in case of hum or noise in your speaker, has a fuse to protect it from Ac problems. Directions for connecting CA2,CA4,CA6,CA9,CA12 are shown in the man