Chest vents are zippered openings on the upper chest of a snow jacket that let air flow directly across your torso. They’re usually mesh-backed to keep snow out while allowing fresh air in.
These vents are great for supplementary airflow, especially if you're touring or riding in warm conditions and need to cool down fast. However, they aren't very common as a primary venting system—most riders rely on underarm pit zips for main temperature control.
One thing to keep in mind: if you wear a backpack, the shoulder straps can block access to chest vents, making them tricky to open or close on the fly. They're best viewed as a bonus feature alongside pit zips rather than a replacement for them.