The Batcone II Excluder is designed to allow bats exit a structure (attic, garage, barn, etc), but will not allow reentry. It is 6" long, with four flexible tabs at one end to attach the excluder over the bats entry/exit point. The bat excluder can be attached using pushpins, staples, duct-tape, etc. Completely re-usable, the Batcone II Excluder is made of a durable polyethylene and will last for many years. For optimal results mount the Batcone II with a slight downward incline.