The Bird Barrier Bat Cone 2 Bat Deterrent (n8-bc05) is tapered so it is a one-way opening. So once they exit, they cannot enter back into the hole. It also has a slick texture so they cannot crawl through the tube.
The Bird Barrier Bat Cone 2 Bat Deterrent will allow bats that are inside a structure to fly out, but will keep them from being able to re-enter at that point. It does not repel bats. If you need a bat repellent, you can use Bonide Bat Magic.
We do not recommend using the Bird Barrier Bat Cone 2 Bat Deterrent (n8-bc05) inside or at the opening of the chimney.