Okay went out and had my Zen U in a open top holster at my waist. The cap came off and was nowhere to be found, I've looked around and does not look like they sell that part. So unless I get another one I have a paper weight. Expensive Hard to get ecig stuff is staying home from now on. Not a good vaping year for me, my ex took my GG Penelope last month. I'm not a happy camper any suggestions on a replacement cap?