1. Download Spark IV (http://gzwn.net/Documents/SparkIV%200.7.0%20Beta%201.zip) or Open IV (www.openiv.com)

2. Using Spark IV/Open IV, go to the "weapons.img" file. This should be located in one of these two locations;

   "Program Files/Rockstar Games/Grand Theft Auto IV/pc/models/cdimages" ~OR~
   "Steam/steamapps/common/Grand Theft Auto IV/pc/models/cdimages"

//I strongly recommend you make a backup of "weapons.img" incase you mess something up or want the bat back.\\


3. Click "Import" and then import the files included with this download. Make sure you hit "Save" when you're done if you want to keep the changes.