 elegant ventilation pathway, which is about equal to a 12 by 12 louver grill. And it's built inside the channel of the door. It also gives you sound privacy. The sound absorbing resonators and acoustic baffles provide this privacy that's similar to a solid door. So really cool how that keeps it quiet. And then you could put whatever size you want. Custom sizes, standard. You can get them inch and three-eighths, inch and three-quarter.