A modular synthesizer format developed by Roger Arrick's Synthesizers.com company. The format is physically compatible with the vintage Moog modules, but not electrically compatible (the Moog modules use S-trigger signals and different power supply voltages). Synthesizers.com set out to duplicate much of the look and feel of the vintage Moogs while employing up-to-date technology; hence, the modules use black panel backgrounds like the Moogs, similar panel graphics, similar knob styles, and the same principles in panel layout. Because of the physical compatibility and the stylistic similarity, the format is also referred to as "Moog Unit", or MU.