Simplex 100W AMP 120V AC 4100-1315 4100-1321 Devices were taken through an inspection process with an inspection sticker applied, appears to have been recertified, everything appears to be damage free but we are unable to test so it is being sold as-is. Please check all pictures and feel free to ask questions. The digital and analog audio amplifiers provide analog audio power to the system speaker circuits. Digital amplifiers decode digitally encoded input signals and analog amplifiers receive analog input signals. A speaker circuit consists of one or more speakers that are driven by the same physical wiring. All of the 100 W amplifiers described in this document are single channel amplifiers; that is, each speaker circuit is driven by the same audio signal. Warehouse BL