The Tomahawk E100CG is a one way door for raccoon, skunk or similar size animals. It measures 20"L x 10"W x 10"H is size. Tomahawk's one way doors have wings to attached the device over the opening, forcing the animal through the one way door. Once they go out through the door they can't get access back in. The E100CG model has a second door stop which prevent raccoons or potentially other animals from pulling on the first door to gain reentry.