The band released two free-form experimental rock albums, "Kraftwerk" (1970) and "Kraftwerk 2" (1972). The albums were mostly exploratory musical improvisations played on a variety of traditional instruments including guitar, bass, drums, organ, flute, and violin. Post-production modifications to these recordings were used to distort the sound of the instruments, particularly audio-tape manipulation and multiple dubbings of one instrument on the same track. Both albums are purely instrumental. Live performances from 1972 to 1973 were mostly made as a duo, using a simple beat-box-type electronic drum machine with preset rhythms taken from an electric organ. Occasionally, they performed with bass players as well. These shows were mainly in Germany, with occasional shows in France. Later in 1973, Wolfgang Flür joined the group for rehearsals, and the unit performed as a trio on the television show "Aspekte" for German television network ZDF.