Pet door for cats, ultra-thin. Outer dimensions: 25 x 23.5 cm. Recommended maximum door thickness: 2.0 cm. I'm selling this because it doesn't fit the thickness of my house door. For more details: https://amz.cx/3DWk 【Important Notes Before Purchase】: ※ The ultra-thin cat door is recommended for a maximum installation thickness of 2.0 cm. If this thickness is exceeded, please choose a regular model cat door. Alternatively, it is recommended to use screws. Please confirm that the "door thickness ≤ 2.0 cm" before placing your order. Installation video: https://youtu.be/VYO3x_NATIM. Thank you.