If you have problems with Wasps and don't want to use vespex or other lures, poisons etc... check out HyfeGate from Beeiq.solutions. Really works! I have them on my hives. They are not a screen or a reduced entrance. It is a tunnel that basically gives the bees a better chance to defend properly. So it's not about keeping the wasps out per se. It is all about giving them a smarter entrance and the chance to defend themselves. And again it really works for me. Lots of wasps around, but not in my hives.