The two most commonly used polyamide grades by far are PA6 and PA66. The remaining members of the polyamide family are primarily used in applications that require unusually high service temperatures or tolerance of moist conditions. Bio-based and transparent (amorphous) PA grades are also available. In machine design purposes PA is often reinforced with glass or - in case of highly demanding applications - with carbon-fiber. Reinforcement changes the characteristics of the material and its applications considerably and therefore I’ll write a separate article on them later. This article focuses on unfilled PA6 and PA66.
Perhaps the most notable absentee from the soundtracks, considering prominence during the series, were Eels , whose song "Novocaine for the Soul" was often used but appeared on none of the CDs. Although appearing in the Christmas Special, Ryuichi Sakamoto 's " Forbidden Colours " was not released on any soundtrack. Gordon Lightfoot 's 'If You Could Read My Mind' was also used multiple times in the series, in the street-artist segment, but he would not give permission for the song to be included in a compilation. " Nineteen Hundred and Eighty-Five " by Paul McCartney and Wings was also used for the oversized men segments but was not on the soundtrack.