VS Series Exterior Venting Units by CellarPro. Self contained and fully charged. These cooling units fit in a hole in the wall and can vent to the outdoors. The VSx (outdoor) units vent warm air outdoors. Performance testing shows that this unit maintains optimal cellar temperature and humidity conditions in extreme conditions up to 110F more effectively than similar units from competing brands. VS units also are significantly quieter than comparable units from other brands.