<prompt> Human: Hello PersonalFinance :-I started investing in 3D-Printing companies about a year ago SSYS, Xone but i go by stocks and i dont have enough time to track all the 3d-printing companies. Anyone is aware of a low MER ETFs that follow this?Thanks  <response>: Putting money into sector ETFs is not investing, it is speculating. If you want misguidance on what ETFs are best for such a narrow market sector as 3D printing, ask the misnamed rinvesting 