All manual PlexiDors share the same key. It doesn’t matter, because the key is used inside the house. A potential intruder can’t use someone else’s key to gain entry through the locked door, because they can’t reach the keyhole.
An advantage of all keys being the same is, it’s easy to get a replacement.
The PlexiDor Electronic is different; it works with collar keys with RFID codes. There are innumerable different codes and every key is unique. The door will only open for codes it recognizes – that is, keys programmed into its memory. The keys that come with it are pre-programmed, but it’s easy to add more, and the current version of the door can remember up to ten different keys.