If you look at the front or rear doors of many vehicles, you'll notice a small, often triangular piece of glass separate from the main roll-down window. This is known as vent glass or quarter glass.
The Purpose of Vent Glass
Historically, these windows actually opened to provide ventilation before air conditioning was standard. Today, they are mostly stationary. They exist to accommodate the curvature of the door and allow the main window glass to roll down completely without hitting the wheel well or door frame.Why They Need Replacement
Vent glass is a common target for vehicle break-ins. Thieves often believe that breaking this smaller window will be cheaper for the owner or make less noise, allowing them to reach in and unlock the door.Unfortunately, because vent glass is a specialized, shaped piece that often comes attached to a specific rubber molding or metal frame, it can actually be more complex to replace than standard door glass.