electronic device black or grey a large, rectangular box one or more knobs or dials two or more input and output jacks a power cord a volume control a power switch
amplifier which has electronic device amplifier which has black or grey amplifier which is a large, rectangular box amplifier which has one or more knobs or dials amplifier which has two or more input and output jacks amplifier which is a power cord amplifier which is a volume control amplifier which is a power switch