Operate Vent and Refill Port

have here is and then you when you're in use you take this cap off it's a vent so that when you're spraying you'll actually be able to you know use it because if we didn't have a vent it wouldn't spray very well. The other portion of this is the paint fill hole. So when you are running out of paint you just take this off and you dump more paint in here and away you go. As painters we all fight this.