I like that this is a proper heating mantle. No more oil baths or heat element sunk into sand for me! The problem is the stirring, it's not properly centered into the mantle. Furthermore, the rotor magnet isn't very strong. These problems, combined with the fact that my magnetic stir rods are off center, makes it impossible for things to stay synced at anything but idle pace. Other than that it's a solid performing unit. It's a little larger than I was expecting though. My 1L round bottom flask has about one and a half inches of space all around it. Could be that my flask is on the small side for 1L, could be that it's by design. I'd prefer a "fit like a glove" sizing, but I guess that's unlikely, and I keep getting told that it's OK anyway. Whatever, it's definitely an upgrade from what I had, but I feel like I could/should have spent a little more on a better unit.Edit: I discovered today that at least part of the problem was that I wasn't using the proper egg shaped stir bars. So I've added a star. After solving that problem, I set out to solve the off center stir problem. Fortunately there are just 3 screws on the bottom that hold the thing together.First thing I found was that the two magnets are being held in place with a piece of ferromagnetic material bridging across them. This created a "magnetic short circuit" of sorts, significantly reducing the "reach" of the stir mechanism's magnet. I replaced this tiny piece with a similar shaped piece of FR4 circuit board. Hard to tell how much that helped, but it couldn't have hurt.Second. Indeed, the hole that was cut for the stir motor was visibly off center from the rest of the device. nothing I could do about this existing hole, but I could do something about how the motor sat in it. I loosened the screws holding down the stir motor then cocked the motor as hard toward the center as I could manage, and while holding, tightened the whole thing down again. After that I tweaked the motor bracket some to make it even