A method and apparatus for controlling the presentation of multi-media content stored on a medium containing a plurality of multi-media content are disclosed. The instrument is formed in one piece from a stiff polymeric material. Further, through omitting the spring or the flange portion, it is unnecessary to provide a space for receiving those members in an inside of the housing, and thus a shape of the housing is simplified. 35; and L+M+N=1; and, wherein R1, R2 and R3 are independently selected from C1-C6 alkyls and derivatives thereof. The method according to the invention comprises an H2S-rich stream recycling stage.