Since its release the Doefper A-100 system is the most diverse system on the market, offering all electronic circuits relevant in music, most of them in different variants. A Polyphonic line and a Slim line of modules completed the system in recent years. Because of their classic layouts these modules are easy to understand, usable in many different ways and often even allow modifications to expand their functionality further. Modules, patch cables and other additional accessories such as keyboards and cases of different sizes are always available for delivery.