Fits 1 or 2 AA35 35W Three-Channel Mixer/Amplifier or PA601 60W Single-Channel Power Amplifier. The Atlas Sound AARMK2-5 Rack Mount Kit (Black) is a 2RU kit designed to work with 1 or 2 or combination Atlas Sound AA35 35W Three-Channel Mixer/Amplifier or PA601 60W Single-Channel Power Amplifier. It mounts the amplifiers to a standard 19 equipment rack