The Bat Valve was developed to act as a one way door to help in the removal of bats that can be installed with ease. Bats can use the tube to leave the location that is being sealed but have a very difficult time in trying to re-enter the space through the tube, when installed correctly. Once the bats have been sealed out and removed un-install and take it to the next location.
This product has three different models:
The TBV-SG3 for soffit returns and gable vents.
The TBV-FLEX2 for corner gaps. Can also be used on bathroom exhaust vents for bird exclusion.
The TBV-FR4 for Ridge Vents and Frieze Board Gaps.