Sure is, 9mm cases that come in most packs of 50. These particular ones were Remington and I use a few of them to hold various tanks and cartos with flavors I'm trying out. They work perfectly and were virtually free! I usually take one of these with me to the couch, bed, office, where ever I may be if I'm vaping, and then I can easily swap out flavors without making a mess or having them fall all over the place.
Edit - I actually came across the idea somewhat by accident. I was cleaning out my closet to make room for a little vaping section I made. In the process I came across like 5 empty boxes of ammo and it immediately hit me. I had a couple of another brand that were white but I prefered the black ones.