When bees swarm they will all try and exit the hive wherever they can. This specially designed device with its lightweight transparent cover draws bees towards the light and the curved angle allows them to observe outside the hive. When they are ready to exit the hive and begin their mating process the pressure of the bees pushes off the cover and indicates the bees have swarmed.
There is no need to check the hive and disturb any remaining bees.
Dimension of the tip placed in the vent: 20x50mm
Caution: the lightweight cap is very fragile do not push on to tightly as it may split.