I really like the K6ARK morse code key, but I have managed to break a couple of them by carelessly storing them in my kits. This case prevents the paddles from being touched while stored. It is designed to hold the key in the case with a bit of tension. The hole in the back allows you to push the key out with your finger.
Adam's Paddle files available here
UPDATE: Based on some feedback, I have added another file that includes another slot at the opposite end to allow the key to be reversed in the holder with the key cable connected. The case can then be used as a handle/holder for a better purchase on the key if you hand hold the key.
The author marked this model as their own original creation.