Characteristics: The frame and the inner plate are made of two inner and outer parts, which are easy to assemble. It can be installed on screen doors, windows and other sheltered areas. Allow your pet to walk in and out freely and also prevent mosquitoes from entering the room. Designed with a strong magnet, this door will automatically close when your pet exits or enters. Easy to control, your pet will enter or exit without being constricted. Technical data: Material: plastic; Color: Black, White (Optional) Size: L, XL (optional) L: Ok. 29 x 24 x 1 cm / 11.42 x 9.45 x 0.39 inch (external dimensions) L: Ok. 25 x 19.7 cm / 9.84 x 7.76 inch (inside dimension) XL: Ok. 45.5 x 35.5 x 1 cm / 17.91 x 13.98 x 0.39 inches (external dimensions) XL: Ok. 40 x 30 cm / 15.75 x 11.81 inch (internal dimension) Weight: approx. 317 ~ 835g Package includes: 1 x pet door; Installation Guide: 1. Cut off the two inserts that control entry and exit. 2. Divide the cat door into two parts. 3. Attach the outer frame to the mesh door and press the pin buckle into the screen mesh. 4. Use glass glue to stick the buckle and screen mesh firmly. 5. Cut the screen mesh in the frame along with the frame. 6. The cut-out screen mesh can be installed between the inner plate to prevent mosquitoes. 7. Hang the inner plate on the frame. 8. Attach another (inner) frame. End. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.