This is Tier One Pack, One of sadly (now only two) of Three packs made by Sierra to expand the Swat 3 TGOTY and Elite Edition arsenal with new weapons it was one of 4 mods on the TGOTY CD, It has new weapons from the Arwin Launcher to the CZ 75. (Tier Two is lost forever due to the closing of an archive site Sierra had of the Tier Two Pack) This file is not by me and I do not take credit for it either, This file originally was on the Swat 3 reunited website.
Man, it is such a shame tier two pack was lost forever :(