The Vivaldi Screen is normally combined with the Vivaldi board, but you can buy it separately. One nice alternative to the Vivaldi Board is to add a honey super on top of an inner cover, with a hole drilled for ventilation aop of the super. Combine this with a Vivaldi Screen and you have something functionally very close to the VivaldiBoard/Vivaldi Screen combination if you include some natural insulation. We use burlap but you can also use sheep wool, cedar shavings or other natural material. The Vivaldi screen increases the surface area of moisture absorption to the top surface of your insulation.
You can also provide emergency winter feeding of Drivert sugar directly through the screen. We find that the bees love congregating up in under the Vivaldi screen in winter because it is the warmest spot in the hive.