A pen case? An unusual key case that makes you think, "Is this a pen case? It is small, so people tend to think it is easy to make, but because it is small, there is a lot of detailed work, so it is a lot of hard work, and it is made with a lot of care.
Zipper type key case. There are four rings inside to store your keys, so they will not damage or snag anything in the bag. The metal fittings on the outside are removable with screws so you can attach your car keys or larger keys.