This is a cat door (also suitable for small dogs) that attaches to a window. I've had it installed for 4 years. The lock on the right side of the door is broken (please see the image). The frame itself is sturdy, as I only removed it after 4 years of installation. However, the plywood on the bottom of the frame is peeling, and there are traces of removed tape and deteriorated sponge tape for draft prevention, but I think it can be repaired with items from a 100-yen shop. I bought it for around 30,000 yen. If anyone would like to use it, please let me know (^^) Size: Height: 131 cm Width: 26.3 cm Thickness: 2.4 cm Door size: 14 cm x 16 cm