This is an Weapon pack from AH of Swat3reunited.com, Its 3 weapons from Quake 3 Arena made by I.D. Software:The Shotgun, Plasma Gun, and Rocket launcher which can all be used in co-op, This pack is NOT by me and I do not take credit for it either.
Drag the file (RAR) to Sierra/Swat3/Mods and place it there, Enable via the swat 3 mod launcher and the mod will be ready to use.