"Stalker" is one of those games that captivate with its unique atmosphere and plot. However, the monotony of the standard game world eventually gets boring, and then experienced modders come into play, releasing mods that "refresh" it.
About gas masks

A gas mask is an indispensable friend of a stalker in the infected Zone, because it protects its wearer from the harmful effects of radiation on the respiratory tract. Stalker gas mask can be purchased from any merchant, removed from a corpse or found in a cache, but on condition that the appropriate modifier is installed.
Newcomers to the game use the device because of its strong protection, but seasoned stalkers prefer to do without it, because during the battle the misted glass distracts. Also, gas masks in the game have a lot of weight and protection from psi-radiation.
Description of the gas mask mod

In "Stalker" mod for gas masks adds an updated dynamic thin, that is, the character's interface will be displayed through the glass of the gas mask. This mod includes ninevarieties of helmets with gas masks, including the groups "Duty", "Freedom" and so on. In addition to the main armor, the player will be able to use bandit equipment, various body armor, Monolith scientific suits, leather jackets and raincoats. A large number of armored suits and exoskeletons have also been added, some of which have unique properties. Ordinary exoskeletons and armored suits can be improved at your discretion. You can put on a gas mask in the "Stalker" at your discretion, as it has increased protection, but can affect the course of the battle.
Now you can remove armor from corpses and try it on your character, and you can look at the gas mask from the side using the added third-person view. As an additional improvement, a flashlight display on the left shoulder of the character has been added to the mod.
Additional updates and installation
Additional updates include updated main menu textures and new equipment at the start of the game. Those characters from whom the stalker takes tasks have been visually changed. The standard advice from independent characters has been replaced with anecdotes that are fun to listen to. The AK-47 has been added to the game with the mod as a basic weapon. The mod is installed after deleting the gamedata folder, then you need to specify the direction to the folder with the game, and the previously deleted folder will be created automatically by the installer.