Atomic force microscopy (AFM), or scanning force microscopy (SFM), is a very high-resolution type of scanning probe microscopy, with demonstrated resolution on the order of fractions of a nm, more than 1000 times better than the optical diffraction limit. The AFM is one of the foremost tools for imaging, measuring, and manipulating matter at the nanoscale. The information is gathered by "feeling" the surface with a mechanical probe. Piezoelectric elements that facilitate tiny but accurate and precise movements on (electronic) command enable the very precise scanning. In some variations, electronic potentials can also be scanned using conducting cantilevers. In more advanced versions, currents can be passed through the tip to probe the electric conductivity or transport of the underlying surface.