Call of duty 4 Custom Classes
In call of duty 4 you can get custom classes at around level 4. In call of duty 4 custom classes allow you to pick a weapon, attachement, perks, grenades, and a whole bunch of other stuff. You can only create call of duty 4 custom classes online, you cannot in single player or splitscreen. Many people customise their classes to create a great gun with perks that help their roles on the team. For example if you are a sniper you will want stopping power, iron lung, and claymores as your perks, so as you can see in call of duty 4 custom classes play a large role in the game.