Tortoise Key Hider 3 "not for all keys !" Susan 06 June 2014 Lovely little tortoise and a great idea, unfortunately he is only big enough for yale keys. I have a era 5 leaver mortice lock key (very common) however, it does not fit into the tortoise body. So will be returning. A note from the team Thanks for the feedback, I'm sorry that the key hider hadn't been suitable for your keys I'm glad out customer services team were able to help. The internal measurements are 2½" x 2¼". It will hold 2 small keys.