The Varroa Trap at Mannlake is what most people would call a screened bottom board, but when used with a solid board underneath (critical) uses the feature of a screen but without the open ventilation to the ground that can cause other problems (pests, too much air movement). I spent a long time researching the virtues of regular sticky board sampling and I can't imagine beekeeping without it. It fits on top of my regular solid board with the opening to the back. Enjambres (a prolific BeeSource contributor who I have a lot of respect for) uses this same configuration and got me interested in it. One day a book will be written about what sticky boards are telling us.What is a Varroa trap?