I recently acquired a set of omni caps to go along with my cardioid caps for my Church Audio CA-11 mics. I wasn't quite sure where/how to store them. I had them on my desk and sitting near them was an empty AO Safety earplug container. Ear plugs used and long gone, but the container seemed like a good size for the caps. Put a little foam in the bottom and top, tested it - looked and felt good. A couple dabs of hot glue, some fleece to soften the lining some more, and a label. Voila - a microphone cap storage case for my CA-11 caps. To give some size perspective, the caps are 12 mm in diameter. The small case is about 1.25" in diameter by about 0.5" high.