The GSG 9 is the German Counter-Terrorist and Special Operations division, that was originally started in 1973 as a special unit of the Bundesgrenzschutz. After the BGS was disbanded and became the Bundespolizei, they were allowed to retain their old BGS unit designator of "GSG 9" to honor them for their outstanding service.
Here is a great history of the GSG 9 on Wikipedia. After reading up on the GSG 9 on the Wiki-page, you will understand why they are considered the best and most elite of all the world's special forces:
My GSG 9 uniform set is dated 1975, which makes it one of the original issue uniforms! I received it from a BGS veteran in Germany who confirmed that it was an actual GSG 9 issue. The original patches had been removed by the original owner / BGS trooper, however the original stitching lines were intact. I matched a replacement set of patches to the original outlines yesterday. The "breast eagle", or GSG 9 qualification patch is unique only to the GSG 9 and is universally recognized as the symbol of the division. Both the jacket and pants are in remarkably good condition, with the exception of the button thread. I will be resewing the buttons to make sure they stay attached!
Here is the album of this early GSG9 Mehrzweckanzug set:
Here are a few old GSG-9 photos showing these uniforms in use: