Using a gaseous form of "Pym particles" kept in a compartment in his belt, Ant-Man had the power to shrink himself (and other people and objects along with himself) to the size of an ant and return to normal. Over time, he has acquired the ability to change size at will, seemingly without the need for the gas. His cybernetic helmet allows rudimentary telepathic communication with insects, and is equipped with sound amplification equipment allowing normal-sized humans to hear him. The helmet also has a retractable plexiglass face shield and a limited air supply. Lang retained his normal strength in ant size.
Scott Lang can also shrink to sub-microscopic size, and thereby enter the countless "subatomic universes".
The pacemaker that Darren Cross made for his heart gave him superhuman abilities where the side-effect has it burning out each heart that is transplanted into him.