So, what the heck is a "Tank Ring"? I'm working up an order on a mini, and the accessories include a Tank Ring as one of the options. If it's useful, I'll add one, but what's it good for? Only ten bucks, but I have to justify everything to my accountant, which is me. If anyone cares, I lost one of my Twists, and if I'm ever going to bite that particular bullet, this seems like the best time.