This download grants the Mechromancer, a 5th playable character class who can summon a destructive robot named Deathtrap. In addition to this new class, this pack also includes bonus items which were included in the Borderlands 2 Premiere Club Pack, including the Gearbox Gold Gun Pack, a Golden Key, which unlocks rare items in the mysterious Sanctuary Loot Chest, and the Vault Hunter’s Relic, which boosts your gear-hunting fortunes.

Go to: http://store.steampowered.com/ and download STEAM client Click "Install Steam" (from the upper right corner) Install and start application, login with your Account name and Password (create one if you don't have). Please follow these instructions to activate a new retail purchase on Steam: Launch Steam and log into your Steam account. Click the Games Menu. Choose Activate a Product on Steam... Follow the onscreen instructions to complete the process. After successful code verification go to the "MY GAMES" tab and start downloading.