made this case for the wife's Amneal epinephrie auto injection pens 0.3mg. wasn't able to find any I liked online. the pens still have a little bit of wiggle room and I thought about adding some foam to one of the ends just to give to some padding and remove the last bit of rattle(but in my option its not bad now). Then pens will only fit in one way the side with the ridges will need to go into the bottom of the case(larger section). the two sections fit together very snuggly and I recommend opening and closing them for a bit until you get a little wear and have the desired opening tension. I have also considered adding a small hole at one end just to allow air to flow in better and remove the suction you get when trying to pull them apart. But for now I wanted it to be more water resistant so I desided to leave it out. If its popular I may come back and add another version with a hole and ridges on the case for grip. Thanks and hope it helps omeone else.