An AFM probe is a sharp tip placed at the free end of a cantilever that is attached to a probe holder. Typical dimensions are on the micrometer scale with the tip radius being a few nanometers to tens of nanometers.
The cantilever is attached to a rectangular chip on the millimeter scale that enables to user to grab the probe and place it in the probe holder so it can be used on an Atomic Force Microscope. AFM tips are made using processes pioneered by the semiconductor industry. Known today as MEMS technology, most probes are made of silicon and silicon nitride.
The tip on the end of the cantilever can be different lengths, sharp or blunt and be coated with different materials to enable different scanning properties including longer wear, material bonding and magnetics.
In addition to different coatings on the tip, the cantilevers are engineered to different specifications so as to interact better with the sample they are scanning and the AFM mode they are using. For example, different frequencies enable faster or slower scanning and the spring constant can enable softer or harder interaction with the sample surface. Probes are considered consumables as they wear out over time.