Note: Size S is a little different from other sizes. It's "thinner".
Function Instruction of the Switches: Turn Red and Green switches to both sides, pet is prevented from entering or exiting house. Turn Red and Green swithes to right side, pet is allowed to enter house, but prevent from exiting house. Turn Red and Green switches to left side, pet is allowed to exit house but prevent from entering house. Turn Red and Green switches to middle, pet can leave and exit any time.