The P.E.S. (Pressurized External Suit) is a piece of equipment on the Zombies map Moon. It gives players the ability to survive in areas that are void of oxygen on the Moon, much like a space suit. The helmet is in the equipment slot and is therefore removable. The P.E.S. is free to take and is right in front of the player after teleporting to the Moon. Because the P.E.S. is free, it can easily be transferred between itself and the Hacker. It is available in every Air Lock throughout the map. Without the P.E.S., the player can spend a maximum of 15 seconds in a vacuum before being downed; the player also will not be affected by the Phasing Zombie's gas. The P.E.S. and the Hacker occupy different equipment slots than Claymores/Trip Mines and therefore will not replace them.
There is no actual reflection of the background on the P.E.S. visor; it only shows a landscape on the moon, no matter where the player is.
Richtofen will call the device "pies" because "P.E.S." somewhat resembles the word "pies".
Players can put on the P.E.S. in three different ways. A player can put it on while standing, which is the regular way of putting it on. If crouching the player can notice that they are putting the P.E.S on slightly to the left. When putting the P.E.S on while prone, the player will put it on left.
In the remastered version of Moon, an authentic first person view is present to match the world model.