I have a few vibrating ones, but they run out of battery so fast - so this one’s even better! It’s got a weighted spring mounted on the inside, so every time I move it makes the plug jump and shake. Makes it -impossible- to ignore, to the point I have to be careful to make sure I’m not doing anything too important at work if I’m going to wear it that day… by the end of the day I’m too distracted to get anything done correctly.