I love love love love Candle Science, but this was such a waste of money. I use a variety of vessels for my candles, from glass to tin to concrete. It doesn't matter what the material of the vessel is, the setter is just not level. It wiggles around and not one time have I ever gotten a centered wick. I'm not slamming it down hard, I'm calibrating the thumbscrew and collar as per the instructions, but it continues to wiggle unsteadily. I even tried it upside down, holding the vessel on top, thinking that may make it steadier. I'm so disappointed because I have a tremor in my hands and placing wicks is not my strongest suit. I really thought this would help, but it doesn't.