The cardboard box has long since been the typical object that Snake uses to camouflage himself into the background and sneak past guards. In
MGS4, the cardboard box will make an appearance alongside a new item called the drum can. The cardboard box has become the main 'camo' item for the games and has been an ongoing gag since the first game and has even made an appearance in the game
Super Smash Brothers Brawl. The box trick only works if you have not already alerted the guards and are not hiding directly in their patrol path. The oil drum serves a similar purpose, however it is bullet proof and you can also use it as a weapon by rolling in it and knocking down foes.